US8693931B2 - Image forming apparatus and fixing device - Google Patents
Image forming apparatus and fixing device Download PDFInfo
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- US8693931B2 US8693931B2 US13/197,360 US201113197360A US8693931B2 US 8693931 B2 US8693931 B2 US 8693931B2 US 201113197360 A US201113197360 A US 201113197360A US 8693931 B2 US8693931 B2 US 8693931B2
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- rubbing
- sheet
- roller
- fixing device
- image
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2215/00—Apparatus for electrophotographic processes
- G03G2215/06—Developing structures, details
- G03G2215/0602—Developer
- G03G2215/0626—Developer liquid type (at developing position)
- G03G2215/0629—Developer liquid type (at developing position) liquid at room temperature
Definitions
- the present invention is related to an image forming apparatus for forming an image on a sheet and a fixing device for fixing the image onto the sheet.
- An image forming apparatus which uses liquid developer is known as a device for forming an image on a sheet.
- This type of image forming apparatuses typically has a fixing device configured to fix images onto sheets.
- the fixing device generates relatively high heat in order to melt toner components in the liquid developer transferred onto the sheet.
- the fixing device uses liquid developer which has characteristics such that its components (carrier solution) permeate into a sheet and high-molecular compounds with dispersed pigment therein deposit on the surface of the sheet.
- the present inventors have discovered disadvantageous properties which are likely to cause peel-off of the image formed on the sheet by means of such liquid developer.
- An object of the present invention is to provide an image forming apparatus and fixing device which is less likely to allow the peel-off of images on a sheet.
- An image forming apparatus includes: a conveying element configured to convey a sheet; an image forming section configured to form the image on the sheet with liquid developer; and a fixing device configured to fix the image onto the sheet, wherein the fixing device includes a rubbing mechanism configured to rub the image on the sheet.
- a fixing device includes: a rubbing mechanism for rubbing an image which is formed with liquid developer.
- FIG. 1A is a schematic view showing a transfer process using liquid developer.
- FIG. 1B is a schematic view showing the transfer process using the liquid developer.
- FIG. 1C is a schematic view showing the transfer process using the liquid developer.
- FIG. 2A is a schematic view showing methodologies of a fixation process after the transfer processes shown in FIGS. 1A to 1C .
- FIG. 2B is a schematic view showing the methodologies of the fixation process performed after the transfer processes shown in FIGS. 1A to 1C .
- FIG. 3 is a graph schematically showing a relationship between a rubbing time and fixation ratio.
- FIG. 4 is a graph schematically showing a result of a screening test performed on various nonwoven fabrics.
- FIG. 5 is a plan view schematically showing a fixing device to which the fixation methodologies shown in FIGS. 2A and 2B are applied.
- FIG. 6 is a schematic side view of the fixing device shown in FIG. 5 .
- FIG. 7 is a schematic side view of the fixing device shown in FIG. 5 .
- FIG. 8 is a cross-sectional view schematically showing an image forming apparatus to which the methodologies of the fixing device shown in FIG. 5 are applied.
- FIG. 9 is a schematic cross-sectional view of the image forming apparatus without circulation devices.
- FIG. 10 is an enlarged view of one of image forming units of the image forming apparatus shown in FIG. 8 .
- FIG. 11A is a schematic view of an experiment performed for verifying the fixation methodologies according to the second embodiment.
- FIG. 11B is a schematic view of the experiment performed for verifying the fixation methodologies according to the second embodiment.
- FIG. 11C is a schematic view of the experiment performed for verifying the fixation methodologies according to the second embodiment.
- FIG. 11D is a schematic view of the experiment performed for verifying the fixation methodologies according to the second embodiment.
- FIG. 12 is a graph showing results of the experiments shown in FIGS. 11A to 11D .
- FIG. 13 is a schematic plan view of a fixing device according to the second embodiment.
- FIG. 14 is a plan view schematically showing operations of the fixing device shown in FIG. 13 .
- FIG. 15A is a side view schematically showing the operations performed by the fixing device shown in FIG. 13 .
- FIG. 15B is a side view schematically showing the operations performed by the fixing device shown in FIG. 13 .
- FIG. 16 is a side view schematically showing the operations performed by the fixing device shown in FIG. 13 .
- FIG. 17 is a schematic side view of a fixing device according to the third embodiment.
- FIG. 18 is a schematic side view of the fixing device according to the third embodiment.
- FIG. 19A is a schematic view of a rubbing roller of a fixing device according to the fourth embodiment.
- FIG. 19B is a schematic view of the rubbing roller of the fixing device according to the fourth embodiment.
- FIG. 20 is a cross-sectional view schematically showing a fixing device and a conveyor according to the fifth embodiment.
- FIG. 21 is a schematic plan view of the fixing device shown in FIG. 20 .
- FIG. 22 is a schematic cross-sectional view of a rubbing roller of the fixing device shown in FIG. 20 .
- FIG. 23 is a schematic cross-sectional view of a rubbing roller configured to rub an image layer on a sheet conveyed by the conveyor shown in FIG. 20 .
- FIG. 24 is a schematic cross-sectional view of the rubbing roller configured to rub the image layer on the sheet conveyed by the conveyor shown in FIG. 20 .
- FIG. 25 is a schematic cross-sectional view of the rubbing roller configured to rub the image layer on the sheet conveyed by the conveyor shown in FIG. 20 .
- FIG. 26 is a cross-sectional view schematically showing a fixing device and a conveyor according to the sixth embodiment.
- FIG. 27 is a schematic cross-sectional view of a rubbing roller configured to rub an image layer on a sheet conveyed by the conveyor shown in FIG. 26 .
- FIG. 28 is a cross-sectional view schematically showing a fixing device and a conveyor according to the seventh embodiment.
- FIG. 29 is a schematic view of a fixing device and a conveyor according to the eighth embodiment.
- FIG. 30A is a schematic view of a separator and a conveyor which are used in a fixing device according to the ninth embodiment.
- FIG. 30B is a schematic view of the separator and the conveyor which are used in the fixing device according to the ninth embodiment.
- FIG. 31A is a schematic view of operations performed by the fixing device shown in FIGS. 30A and 30B .
- FIG. 31B is a schematic view of the operations performed by the fixing device shown in FIGS. 30A and 30B .
- FIG. 32A is a schematic view of other operations performed by the fixing device shown in FIGS. 30A and 30B .
- FIG. 32B is a schematic view of other operations performed by the fixing device shown in FIGS. 30A and 30B .
- FIG. 33 is a schematic view of a conveyor and a fixing device according to the tenth embodiment.
- FIG. 34 is a schematic view of a separator and a conveyor which are used in a fixing device according to the eleventh embodiment.
- FIG. 35 is a side view schematically showing a fixing device and a conveyor according to the twelfth embodiment.
- FIG. 36 is a plan view schematically showing the fixing device and the conveyor according to the twelfth embodiment.
- FIG. 37 is a front view schematically showing the fixing device and the conveyor according to the twelfth embodiment.
- FIG. 38 is a cross-sectional view schematically showing one of connectors of the fixing device shown in FIGS. 35 to 37 .
- FIG. 39 is a side view schematically showing an improved fixing device and a conveyor according to the twelfth embodiment.
- FIG. 40 is a plan view schematically showing the improved fixing device and a conveyor according to the twelfth embodiment.
- FIG. 41 is a plan view schematically showing a fixing device and a conveyor according to the thirteenth embodiment.
- FIG. 42 is a cross-sectional view schematically showing one of connectors of the fixing device shown in FIG. 41 .
- FIG. 43 is a schematic view of a connection between the connectors shown in FIG. 42 .
- FIG. 44 is a plan view schematically showing the fixing device of the thirteenth embodiment which performs a fixation process on a relatively small sheet.
- FIG. 45 is a plan view schematically showing operations of the fixing device according to the thirteenth embodiment which performs the fixation process on a relatively large sheet.
- FIG. 46 is a plan view schematically showing operations of the fixing device according to the thirteenth embodiment which performs the fixation process on a relatively small sheet.
- FIG. 47 is a schematic view of a fixing device and a conveyor according to the fourteenth embodiment.
- FIG. 48 is a schematic view of a conveyor and a fixing device according to the fifteenth embodiment.
- FIG. 49A is a schematic view of a separator and a conveyor which are used in a fixing device according to the sixteenth embodiment.
- FIG. 49B is a schematic view of the separator and conveyor which are used in the fixing device according to the sixteenth embodiment.
- FIG. 50 is a schematic view of the separator and conveyor which are used in the fixing device according to the sixteenth embodiment.
- FIG. 51A is a schematic view of other operations performed by the fixing device according to the sixteenth embodiment.
- FIG. 51B is a schematic view of other operations performed by the fixing device according to the sixteenth embodiment.
- FIG. 52 is a schematic view of a conveyor and a fixing device according to the seventeenth embodiment.
- FIG. 53 is a schematic view of a fixing device and a conveyor according to the eighteenth embodiment.
- FIG. 54 is a perspective view of a rubbing member.
- FIG. 55 is a plan view of the rubbing member and an endless belt.
- FIG. 56 is a schematic view of a fixing device and a conveyor according to the nineteenth embodiment.
- FIG. 57 is a perspective view of a rubbing member.
- FIG. 58 is a plan view of the rubbing member and an endless belt.
- FIG. 59 is a schematic view of the fixing device.
- FIG. 60 is a schematic view of the fixing device.
- FIG. 61 is a plan view of the rubbing member and the endless belt.
- FIG. 62 is a schematic view of a modified fixing device and conveying device according to the eighteenth embodiment.
- FIG. 63 is a schematic view of a fixing device and a conveyor according to the twentieth embodiment.
- FIG. 64 is a perspective view of the fixing device and the conveyor.
- FIG. 65 is a perspective view of a vibration motor.
- FIG. 66 is a plan view of an endless belt on which a sheet is placed.
- FIG. 67 is a schematic view of a fixing device and a conveyor according to the twenty-first embodiment.
- FIG. 68 is a schematic view of a fixing device and a conveyor according to the twenty-second embodiment.
- FIGS. 1A to 1C schematically show transfer processes for transferring an image obtained by means of liquid developer, respectively.
- the transfer processes are sequentially performed in the order of FIGS. 1A to 1C . Transferring an image to a sheet and the image obtained after the transfer are described with reference to FIGS. 1A to 1C .
- FIG. 1A is a schematic cross-sectional view of a liquid layer L of liquid developer used for forming an image, which is transferred from an image carrier 100 to a sheet S.
- the image carrier 100 may be, for example, a transfer belt which is provided in an image forming apparatus (e.g., a printer, a copy machine, a facsimile device, or a combined machine with these functions) for forming an image by means of liquid developer.
- the image carrier 100 conveys the liquid layer L of the liquid developer for forming an image to a transfer position, where the image is transferred to the sheet S.
- the liquid layer L of the liquid developer for forming the image includes carrier liquid C, colored particles P for coloring the image, and polymer compounds R dissolved or swollen in the carrier liquid C.
- the colored particles P which are dispersed in the carrier liquid C, are electrostatically attracted to the sheet S. Consequently, the colored particles P adhere to the sheet S to form the image thereon.
- the attraction of the colored particles P to the sheet S is accomplished by, for example, an electric field, which traverses the sheet S. The methodologies relating to this attraction of the colored particles P to the sheet S is described in detail hereinafter in association with the image forming apparatus.
- FIG. 1B schematically shows the carrier liquid C permeating into the sheet S.
- the carrier liquid C with a relatively low kinetic viscosity permeates into the sheet S and forms a permeation layer PL in a surface layer of the sheet S.
- the polymer compounds R in the liquid layer L of the liquid developer becomes more concentrated as the carrier liquid C permeates into the sheet S.
- the polymer compounds R of the liquid layer L deposit.
- the electrostatic adhesion of the colored particles P to the sheet S occurs prior to the deposition of the polymer compounds R.
- the polymer compounds R which deposit on the surface of the sheet S, form a coating layer which is stacked on the layer of the color particles P forming the image on the sheet S.
- FIGS. 2A and 2B schematically show fixation processes performed after the transfer process.
- FIG. 2A schematically shows the fixation process.
- FIG. 2B is a schematic cross-sectional view of the sheet S obtained after the fixation process. Methodologies of the fixation process is described with reference to FIGS. 1A to 2B .
- the carrier liquid C substantially permeates into the sheet S, so that an image layer I with the polymer compounds R and the colored particles P is formed on the sheet S.
- the image layer I is not applied with any physical force except for a pressure and electric field generated during transferring the liquid layer L (image) from the image carrier 100 to the sheet S. Therefore, before the fixation process, a physical bond between the image layer I and the sheet S is relatively weak, so that the image layer I may be peeled off as a result of a peel test using tape described hereinafter.
- FIG. 2A shows a rubbing plate 200 exemplified as the fixing device and/or the rubbing mechanism.
- the rubbing plate 200 has, for example, a substantially cuboid substrate 210 and a nonwoven fabric 220 which covers the surface of the substrate 210 .
- the layer of the nonwoven fabric 220 which forms the lower surface of the rubbing plate 200 and faces the image layer I is exemplified as the contact surface.
- a polypropylene nonwoven fabric is used as the nonwoven fabric 220 .
- a polytetrafluoroethylene (PTFE) nonwoven fabric with a dynamic friction coefficient of 0.10 referred to as “PTFE felt A” hereinafter
- a polytetrafluoroethylene (PTFE) nonwoven fabric with a dynamic friction coefficient of 0.13 referred to as “PTFE felt B” hereinafter
- polyester felt polyethylene terephthalate felt
- PET felt polyamide felt
- wool felt or wool felt
- the rubbing plate 200 which is placed on the image layer. I of the sheet S, is moved on the image layer I along the upper surface of the sheet S. As a result, some of the components of the image layer I (the colored particles P and/or the polymer compounds R) are wedged into the surface layer of the sheet S (anchor effect), as shown in FIG. 2B . Thus, the physical bond between the image layer I and the sheet S is strengthened.
- the upper surface of the image layer I is covered with the polymer compounds R. Therefore, the colored particles P for coloring the image, which are covered with the coated layer of the polymer compounds R, are appropriately protected by a strong resin film which is formed by the rubbing operation of the rubbing plate 200 . Thus it becomes less likely that the rubbing operation of the rubbing plate 200 causes damages to the image.
- FIG. 3 is a graph schematically showing a relationship between a time period (rubbing time), during which the rubbing plate 200 slides on the image layer I, and fixation ratio of the image layer I. The relationship between the rubbing time and the fixation ratio is described with reference to FIGS. 2A to 3 .
- the rubbing time shown on the horizontal axis of the graph shown in FIG. 3 indicates the time length during which a given region on the image layer I is in contact with the reciprocating rubbing plate 200 .
- a fixation ratio FR shown on the vertical axis of the graph shown in FIG. 3 is calculated by means of the following formula, where D 0 represents density of the image obtained before peeling a tape attached to the image layer I, and D 1 represents density of the image obtained after peeling the tape attached to the image layer I.
- FR (%) D 1 /D 0 ⁇ 100 [Formula 1]
- the tape used for evaluating the fixation ratio FR was Mending Tape produced by 3M.
- the Mending Tape was attached onto the image layer I by means of a dedicated tool. Therefore, attachment strengths between the image layer I in a test sample and the Mending Tape are kept substantially constant among data points shown in the graph of FIG. 3 .
- the Mending Tape was pressed to the image layer I of the test sample, and then was peeled off from the image layer I by means of a dedicated tool at a substantially constant peeling angle and substantially constant peeling speed.
- the image density of the test sample was measured by SpectroEye, which is a spectrophotometer produced by Sakata Inx Eng. Co., Ltd.
- the image layer I may achieve a relatively high fixation ratio FR. Rubbing the image layer I for less than one second indicates a drastic increase in the fixation ratio FR of the image layer I. It should be noted that weight of the rubbing plate 200 is appropriately defined such that the surface of the image layer I is damaged.
- FIG. 4 is a graph schematically showing relationships of various nonwoven fabrics 220 to the fixation ratios FR. The relationship between each nonwoven fabric 220 and each fixation ratio FR is described with reference to FIGS. 2A to 4 .
- the horizontal axis of FIG. 4 represents types of nonwoven fabrics 220 .
- the PTFE felt A, PTFE felt B, polypropylene nonwoven fabric, polyester felt, PET felt, polyamide felt, and wool felt are used in this test.
- the left vertical axis of FIG. 4 represents the abovementioned fixation ratios FR.
- the fixation ratios FR are expressed by bar graphs in FIG. 4 . It should be noted that all types of the nonwoven fabrics 220 used in this test achieved relatively high fixation ratios FR in a longer rubbing time than one second. Therefore, the fixation ratios FR shown in FIG. 4 are calculated on the basis of a rubbing time of 0.625 seconds in order to screen out relatively effective types of nonwoven fabrics 220 .
- the right vertical axis of FIG. 4 represents dynamic friction coefficient of each nonwoven fabric 220 shown by a dot in FIG. 4 .
- Lower dynamic friction coefficients are advantageous because of less impingement on conveyance of the sheet S and less damage to the image layer I.
- the PTFE felt A achieves the lowest dynamic friction coefficient and the highest fixation ratio FR. It is, therefore, clear that the PTFE felt A is the most advantageous among the tested nonwoven fabrics 220 .
- Any nonwoven fabric material which is not shown in FIG. 4 , may be used as the nonwoven fabric 220 .
- a nonwoven fabric material with a dynamic friction coefficient of 0.50 or lower is used as the nonwoven fabric 220 . It is less likely that such a nonwoven fabric material with a dynamic friction coefficient of 0.50 or lower may impinge on the conveyance of the sheet S and damage to the image layer I.
- FIG. 5 is a schematic plan view of a fixing device configured to fix the image layer I to the sheet S by means of the aforementioned fixation methodologies, and a conveyor configured to convey the sheet S, which passes through the fixing device.
- the fixing device is described with reference to FIGS. 2A , 2 B and 5 .
- a fixing device 300 comprises a rubbing roller 310 which comes in contact with the upper surface of the sheet S.
- the rubbing roller 310 includes a tubular contact cylinder 311 which contacts the upper surface of the sheet S and a shaft 312 which projects from each end surface of the contact cylinder 311 .
- One rotatable end of the shaft 312 is supported by a bearing stored in a housing 320 .
- a gear 321 is mounted on the other end of the shaft 312 .
- An image is formed on the upper surface of the sheet S of FIG. 5 by means of liquid developer.
- the contact cylinder 311 configured to rub the image on the upper surface of the sheet S is exemplified as the rubbing mechanism.
- the fixing device 300 has a motor 330 coupled to the gear 321 .
- the motor 330 configured to rotate the contact cylinder 311 is exemplified as a drive mechanism.
- the conveyor includes an upstream conveyor 410 before the upstream of the fixing device 300 and a downstream conveyor 420 after the downstream of the fixing device 300 .
- the upstream and downstream conveyors 410 , 420 are exemplified as conveying elements configured to convey the sheet S.
- FIG. 5 shows a vector directed from the upstream conveyor 410 to the downstream conveyor 420 .
- the direction of the vector in FIG. 5 is exemplified as the first direction D 1 indicating a conveying direction of the sheet S.
- the length of the vector in FIG. 5 is exemplified as the first speed V 1 indicating a conveying speed for the sheet S.
- the upstream and downstream conveyors 410 , 420 both together convey the sheet S in the first direction D 1 at the first speed V 1 .
- FIG. 6 is a schematic side view of the fixing device 300 and the conveyors (the upstream and downstream conveyors 410 , 420 ).
- the fixing device 300 and the conveyors (the upstream and downstream conveyors 410 , 420 ) are described with reference to FIGS. 2A to 6 .
- the upstream conveyor 410 includes an upper roller 411 which contacts the upper surface of the sheet S, and a lower roller 412 which contacts the lower surface of the sheet S.
- the upper roller 411 includes a pair of journals 413 , 414 .
- the rotatable journal 413 is supported by a bearing stored in a housing 415 .
- a gear 416 is mounted on the journal 414 .
- the upstream conveyor 410 comprises an upstream motor 417 .
- the upstream motor 417 is coupled to the gear 416 .
- the upstream conveyor 410 comprises an upstream support mechanism 430 configured to elastically support the lower roller 412 .
- the lower roller 412 includes a journal 418 which is connected to the upstream support mechanism 430 .
- the upstream support mechanism 430 comprises a bearing 431 which supports the rotatable journal 418 , and an elastic element 432 (e.g., a coil spring) which connects the bearing 431 with a supporting surface F supporting the upstream conveyor 410 , the downstream conveyor 420 and the fixing device 300 .
- the lower roller 412 pushed upward by the elastic element 432 works together with the upper roller 411 to hold the sheet S therebetween. As a result, the sheet S held between the upper and lower rollers 411 , 412 is conveyed to the fixing device 300 by drive of the upstream motor 417 .
- the downstream conveyor 420 includes an upper roller 421 which contacts the upper surface of the sheet S, and a lower roller 422 which contacts the lower surface of the sheet S.
- the upper roller 421 includes a pair of journals 423 , 424 .
- the rotatable journal 423 is supported by a bearing stored in a housing 425 .
- a gear 426 is mounted on the journal 424 .
- the downstream conveyor 420 comprises a downstream motor 427 .
- the downstream motor 427 is coupled to the gear 426 .
- the downstream conveyor 420 comprises a downstream support mechanism 440 configured to elastically support the lower roller 422 .
- the lower roller 422 includes a journal 428 which is connected to the downstream support mechanism 440 .
- the downstream support mechanism 440 comprises a bearing 441 which supports the rotatable journal 428 , and an elastic element 442 (e.g., a coil spring) which connects the bearing 441 with the supporting surface F supporting the upstream conveyor 410 , the downstream conveyor 420 and the fixing device 300 .
- the lower roller 422 pushed upward by the elastic element 442 works together with the upper roller 421 to hold the sheet S therebetween. As a result, the sheet S held between the upper and lower rollers 421 , 422 is pulled out from the fixing device 300 by drive of the downstream motor 427 .
- the contact cylinder 311 comprises a substantially cylindrical elastic layer 313 which surrounds the circumferential surface of the shaft 312 , and a nonwoven fabric layer 314 which covers the outer circumferential surface of the elastic layer 313 .
- the elastic layer 313 is formed by using, for example, sponge or other softer elastic material.
- the nonwoven fabric layer 314 is formed by using, for example, any of the nonwoven fabrics described in the context of FIG. 4 .
- the fixing device 300 comprises a backup roller 340 disposed below the rubbing roller 310 .
- the backup roller 340 includes a substantially cylindrical support tube 341 formed by using sponge or other soft and elastic material, and a metallic shaft 342 inserted into the support tube 341 .
- the fixing device 300 includes a press mechanism 350 configured to press the backup roller 340 to the rubbing roller 310 .
- the press mechanism 350 includes a bearing 351 which supports each of rotatable ends of the shaft 342 projecting from the end surface of the support tube 341 , and an elastic element 352 (e.g., a coil spring) which connects the bearing 351 with the supporting surface F supporting the upstream conveyor 410 , the downstream conveyor 420 and the fixing device 300 .
- an elastic element 352 e.g., a coil spring
- the elastic element 352 biases the backup roller 340 toward the rubbing roller 310 .
- the nonwoven fabric layer 314 and/or the elastic layer 313 is compressed and deformed to form a substantially flat upper nip surface N 1 along the upper surface of the sheet S passing through the fixing device 300 .
- the circumferential surface of the support tube 341 is compressed and deformed as well to form a substantially flat lower nip surface N 2 along the lower surface of the sheet S passing through the fixing device 300 .
- the upper nip surface N 1 which contacts the image (image layer I) formed on the upper surface of the sheet S is exemplified as the contact surface.
- a vector shown above the upper nip surface N 1 in FIG. 6 indicates a direction and speed of the movement of the upper nip surface N 1 .
- the motor 330 rotates the rubbing roller 310 such that the upper nip surface N 1 moves in the first direction D 1 .
- the rotating speed of the motor 330 is set such that the upper nip surface N 1 moves at a second speed V 2 , which is different from the first speed V 1 and defined by the upstream and downstream conveyors 410 , 420 .
- the image layer I formed on the sheet S is rubbed and fixed by the upper nip surface N 1 while the sheet S passes in between the upper and lower nip surfaces N 1 , N 2 according to the methodologies described in the context of FIGS. 2A and 2B .
- the second speed V 2 shown in FIG. 6 is greater than the first speed V 1 .
- the second speed V 2 may be lower than the first speed V 1 .
- the difference between the first and second speeds V 1 , V 2 is defined by a relationship between the rotating speed of the motor 330 and the rotating speed of the upstream/downstream motors 417 , 427 , and/or a relationship between the diameter of the rubbing roller 310 and the diameters of the upper rollers 411 , 421 .
- the motors 330 , 417 , 427 are individually allocated to the fixing device 300 , the upstream conveyor 410 and the downstream conveyor 420 , respectively.
- the fixing device 300 , the upstream conveyor 410 and the downstream conveyor 420 may be driven by a common motor as a drive source.
- the difference between the first and second speeds V 1 , V 2 may be defined by a gear mechanism formed between the common motor and each of the fixing device 300 , the upstream conveyor 410 and the downstream conveyor 420 .
- the single fixing device 300 is situated between the upstream and downstream conveyors 410 , 420 .
- several fixing devices 300 may be situated between the upstream and downstream conveyors 410 , 420 .
- the fixing devices 300 may contribute to an extension of the rubbing time described in the context of FIG. 3 .
- FIG. 7 schematically shows other operations performed by the fixing device 300 .
- the operations of the fixing device 300 are described with reference to FIGS. 5 to 7 .
- the motor 330 may rotate the rubbing roller 310 such that the upper nip surface N 1 moves in a second direction D 2 opposite to the first direction D 1 .
- the nonwoven fabric layer 314 with a relatively low dynamic friction coefficient allows a stable conveyance of the sheet S under the rotation of the rubbing roller 310 rotating in the opposite direction to the conveying direction of the sheet S.
- FIG. 8 is a schematic view of an image forming apparatus to which the methodologies of the fixation technology described in the context of FIGS. 1A to 7 are applied.
- FIG. 9 is a schematic cross-sectional view of a color printer without circulation devices.
- FIG. 10 is an enlarged cross-sectional view of one of image forming units.
- the image forming apparatus configured to form images is described with reference to FIGS. 1A to 1C and FIGS. 5 to 10 . It should be noted that the image forming apparatus shown in FIGS. 8 to 10 is a color printer.
- the image forming apparatus may be a copy machine, a facsimile device, a combined machine having these functions, or another device configured to form images on sheet S.
- the color printer 1 comprises an upper main portion 1 A configured to store various units and parts for forming images, and a lower main portion 1 B which is disposed under the upper main portion 1 A and stores circulation devices LY, LM, LC, LB (liquid mixture supply systems) for corresponding colors.
- circulation devices LY, LM, LC, LB liquid mixture supply systems
- a pipe and alike for connecting the upper and lower main portions 1 A, 1 B to each other is omitted herein.
- the circulation devices LY, LM, LC, LB circulate the liquid developer which is used in an image forming process executed by the upper main portion 1 A.
- Liquid developer circulation technologies used in a well-known image forming apparatus may be appropriately used in the configurations and methodologies of the circulation devices LY, LM, LC, LB.
- the upper main portion 1 A includes a tandem type image forming section 2 configured to form a toner image on the basis of image data, a sheet storage 3 configured to store sheets S, a secondary transfer portion 4 configured to transfer a toner image formed by the image forming section 2 onto the sheet S, a fixing portion 5 configured to fix the transferred toner image onto the sheet S, a discharge portion 6 used to discharge the sheet S on which the toner image is completely fixed, and a conveying portion 7 configured to convey the sheet S from the sheet storage 3 to the discharge portion 6 .
- the methodologies of the fixation technologies described in the context of FIGS. 1A to 7 are applied to the fixing portion 5 .
- the image forming section 2 configured to form an image on a sheet S by using the liquid developer comprises an intermediate transfer belt 21 , a cleaning portion 22 configured to clean the intermediate transfer belt 21 , and the image forming units FY, FM, FC and FB corresponding to colors of yellow (Y), magenta (M), cyan (C), and black (Bk).
- the intermediate transfer belt 21 corresponds to the image carrier 100 described in the context of FIGS. 1A to 1C .
- the image forming section 2 comprises a drive roller 41 which drives the looped intermediate transfer belt 21 , and an idler 49 which is rotated by a traveling motion of the intermediate transfer belt 21 .
- the electrically-conductive intermediate transfer belt 21 is wrapped around the drive roller 41 and the idler 49 .
- the width of the intermediate transfer belt 21 is greater than the maximum width of the sheet S accepted by the color printer 1 .
- the drive roller 41 corresponds to the upper roller 411 of the upstream conveyor 410 described in the context of FIGS. 5 to 7 .
- An upward conveying direction of the sheet S defined by the drive roller 41 is exemplified as the first direction D 1 .
- the conveying speed of the sheet S defined by the drive roller 41 is exemplified as the first speed V 1 .
- the side of the intermediate transfer belt 21 which faces the outside during a circulation drive motion is referred to as “outer surface” and the other side as “inner surface.”
- the image forming units FY, FM, FC and FB are disposed side by side near the intermediate transfer belt 21 between the cleaning portion 22 of the intermediate transfer belt 21 and the secondary transfer portion 4 .
- Each of the image forming units FY, FM, FC and FB comprises a photoreceptor drum 10 , a charger 11 , an exposure device 12 , a developing device 14 , a primary transfer roller 20 , a cleaning device 26 , a neutralization device 13 , and a removing roller 30 .
- the closest image forming unit FB to the secondary transfer portion 4 among the image forming units FY, FM, FC, FB is not provided with the removing roller 30 , but the rest of its configurations is the same as those of the image forming units FY, FM and FC.
- the circulation devices LY, LM, LC and LB correspond to the image forming units FY, FM, FC and FB, respectively.
- the circulation devices LY, LM, LC and LB supply and recover the liquid developer of the corresponding colors, respectively.
- the circumferential surface of the tubular photoreceptor drum 10 is configured to carry a toner image with charged toner (charged to a positive polarity in the present embodiment).
- the photoreceptor drum 10 coming into contact with the intermediate transfer belt 21 rotates to follow the travelling direction of the intermediate transfer belt 21 .
- the charger 11 uniformly charges the surface of the photoreceptor drum 10 .
- the exposure device 12 comprises, for example, an LED light source.
- the light source of the exposure device 12 emits light to the uniformly charged surface of the photoreceptor drum 10 , on the basis of the image data input from external equipment. As a result, an electrostatic latent image is formed on the surface of the photoreceptor drum 10 .
- the liquid developing device 14 holding the liquid developer with the colored particles P, the carrier liquid C and the polymer compounds R faces the electrostatic latent image formed on the surface of the photoreceptor drum 10 , so that the colored particles P and the polymer compounds R adhere to the electrostatic latent image. As a result, the electrostatic latent image is developed into a colored image with the colored particles P.
- the developing device 14 includes a developer container 140 , a developing roller 141 , a feed roller 142 , a supporting roller 143 , a blade 144 which contacts the feed roller 142 , a blade 145 which cleans the developing roller 141 , a recovery device 146 which recovers the liquid developer, and a charger 147 which charges the developing roller 141 .
- the liquid developer after adjusting concentrations of the colored particles P and the polymer compounds R in the carrier liquid C is fed from a feed nozzle 278 into the developer container 140 . It should be noted that the liquid developer is fed toward a nip portion between the feed and supporting rollers 142 , 143 . An excess of the liquid developer drops below the supporting roller 143 and accumulates on the bottom of the developer container 140 . The accumulated liquid developer is recovered through a pipe 82 by using the circulation devices LY, LM, LC LB.
- the supporting roller 143 which is disposed substantially in the middle of the developer container 140 , abuts the upper feed roller 142 to form the nip, portion therebetween.
- a groove for holding the liquid developer is formed on the circumferential surface of the feed roller 142 .
- the liquid developer fed from the feed nozzle 278 is temporarily accumulated in the nip portion between the supporting and feed rollers 143 , 142 .
- the liquid developer held in the groove of the feed roller 142 at the nip portion is delivered to the upper developing roller 141 .
- the blade 144 which is brought into contact with the circumferential surface of the feed roller 142 regulates an amount of the liquid developer held in the groove of the feed roller 142 .
- the excessive liquid developer, which is scraped off by the blade 144 is received by the bottom of the developer container 140 .
- the developing roller 141 which is disposed at an upper opening of the developer container 140 , contacts the feed roller 142 .
- the rotating directions of the developing and feed rollers 141 , 142 are defined such that the circumferential surface of the developing roller 141 moves in an opposite direction to the feed roller 142 at the nip portion, which is formed between the developing and feed rollers 141 , 142 .
- the liquid developer held on the circumferential surface of the feed roller 142 is delivered to the circumferential surface of the developing roller 141 . Because the layer thickness of the liquid developer on the feed roller 142 is appropriately regulated, the liquid developer on the surface of the developing roller 141 is adjusted to have a suitable thickness for forming images.
- the surface of the developing roller 141 which receives the liquid developer, moves above the charger 147 .
- the charger 147 provides charging potential having the same polarity as the charged polarity of the colored particles P.
- the colored particles P of the liquid developer carried on the developing roller 141 moves to the surface side of the developing roller 141 .
- the surface of the developing roller 141 contacts the photoreceptor drum 10 after passing the charger 147 .
- the toner image based on the image data is formed on the surface of the photoreceptor drum 10 by a difference in potential between the electrostatic latent image on the surface of the photoreceptor drum 10 and a development bias applied to the developing roller 141 .
- the circumferential surface of the developing roller 141 contacts the photoreceptor drum 10 and then with the blade 145 .
- the blade 145 removes the liquid developer on the surface of the developing roller 141 after the developing operation performed on the photoreceptor drum 10 .
- the recovery device 146 recovers the liquid developer removed by the blade 145 , and then sends the liquid developer to a pipe 81 of each circulation devices LY, LM, LC, LB.
- the liquid developer flows downward along the surface of the blade 145 .
- the recovery device 146 may preferably have delivery rollers to assist in delivering the liquid developer.
- the primary, transfer roller 20 works with the photoreceptor drum 10 to hold the intermediate transfer belt 21 therebetween. Voltage having an opposite polarity (negative polarity, in the present embodiment) to that of the colored particles P on the photoreceptor drum 10 is applied from a power source (not shown) to the primary transfer roller 20 .
- the primary transfer roller 20 applies, to the intermediate transfer belt 21 , the voltage with the opposite polarity to that of the toner.
- the colored particles P and the polymer compounds R are attracted to the outer surface of the electrically-conductive intermediate transfer belt 21 .
- the intermediate transfer belt 21 then carries and conveys the toner image to the sheet S.
- the cleaning device 26 which removes the liquid developer remaining on the photoreceptor drum 10 without being transferred from the photoreceptor drum 10 to the intermediate transfer belt 21 , comprises a developer conveying screw 261 and a cleaning blade 262 .
- An end of the planar cleaning blade 262 which extends toward the rotation axis of the photoreceptor drum 10 slides on the surface of the photoreceptor drum 10 .
- the cleaning blade 262 scrapes the liquid developer remaining on the photoreceptor drum as the rotation of the photoreceptor drum 10 .
- the scraped liquid developer is temporarily stored in the cleaning device 26 .
- the conveying screw 261 disposed in the cleaning device 26 conveys the residual developer to the outside.
- the neutralization device 13 with a neutralization light source neutralize the surface of the photoreceptor drum 10 using the light from the light source, after the liquid developer is removed by the cleaning blade 262 .
- the substantially tubular removing roller 30 contacts the intermediate transfer belt 21 .
- the removing roller 30 disposed between the image forming units FY, FM removes the carrier liquid C from the liquid developer transferred from the image forming unit FY to the intermediate transfer belt 21 .
- the removing roller 30 disposed between the image forming units FM, FC removes the carrier liquid C from the liquid developer transferred from the image forming unit FM to the intermediate transfer belt 21 .
- the removing roller 30 disposed between the image forming units FC, FB removes the carrier liquid C from the liquid developer transferred from the image forming unit FC to the intermediate transfer belt 21 . Because the image forming unit FB does not have the removing roller 30 as described above, the intermediate transfer belt 21 carries the liquid developer including the carrier liquid C, like the image carrier 100 shown in FIGS. 1A to 1C .
- the sheet storage 3 configured to store sheets S is disposed in a lower part of the upper main portion 1 A.
- the sheet storage 3 includes a feed cassette configured to store sheets S.
- the secondary transfer portion 4 configured to transfer the image formed on the intermediate transfer belt 21 to the sheet S comprises a secondary transfer roller 42 , which faces the drive roller 41 for driving the intermediate transfer belt 21 .
- the secondary transfer roller 42 corresponds to the lower roller 412 of the upstream conveyor 410 described in the context of FIGS. 5 to 7 .
- the secondary transfer roller 42 generates an electric field between the secondary transfer roller 42 and the intermediate transfer belt 21 to attract the colored particles P to the sheet S, as described in the context of FIGS. 1A to 1C .
- the fixing portion 5 disposed above the secondary transfer portion 4 utilizes the methodologies of the fixation technologies described in the context of FIGS. 1A to 7 , to fix the toner image to the sheet S. Therefore, the fixing portion 5 comprises the rubbing roller 310 and the backup roller 340 which are described in the context of FIGS. 5 to 7 . As described above, the rubbing roller 310 rubs the image on the sheet S, so that the fixation process is appropriately performed. In addition, because the rubbing roller 310 is wide enough to rub the entire image, gloss of the image is evenly changed by the contact with the rubbing roller 310 . As a result, it is less likely that the gloss of the image is locally changed even if a user touches the image on the sheet S.
- the sheet S onto which the toner image is fixed by the fixing portion 5 is discharged to the discharge portion 6 disposed in an upper part of the color printer 1 .
- the conveying portion 7 having several conveying roller pairs conveys the sheet S from the sheet storage 3 to the secondary transfer portion 4 , the fixing portion 5 , and the discharge portion 6 sequentially in this order.
- the liquid developer includes the electrically insulating carrier liquid C and the colored particles P dispersed in the carrier liquid C.
- This liquid developer also contains the polymer compounds R.
- the liquid developer preferably has a viscosity of to 400 mPa ⁇ s at a measurement temperature of 25° C.
- the viscosity of the liquid developer (at the measurement temperature of 25° C.) is preferably 40 to 300 mPa ⁇ s, and more preferably 50 to 250 mPa ⁇ s.
- the electrically insulating carrier liquid C which generally works as liquid carrier enhances electrical insulation of the liquid developer.
- electrically insulating organic solvent having a volume resistivity of 10 12 ⁇ cm or above at 25° C. (i.e., an electrical conductivity of 1.0 pS/cm or lower) is preferably used as the electrically insulating carrier liquid C.
- carrier liquid which may further dissolve the polymer compounds R described hereinafter, is preferably used (the one with relatively high solubility for the polymer compounds R).
- the viscosity and type of the carrier liquid C as well as the compounding amount therein are appropriately adjusted and selected in order to obtain the 30 to 400 mPa ⁇ s viscosity (at the measuring temperature of 25° C.) in the entire liquid developer.
- the viscosity of the liquid developer depends on a combination of the organic solvent used as the carrier liquid C and the organic polymer compounds R, which is described hereinafter. Therefore, the type and compounding amount of the organic solvent are appropriately determined in response to a desired viscosity of the liquid developer and the selected type of polymer compounds R.
- Liquid n-paraffinic hydrocarbons, iso-paraffinic hydrocarbons, halogenated aliphatic hydrocarbons, branched aliphatic hydrocarbons, and a mixture thereof are exemplified as the aliphatic hydrocarbons.
- n-hexane, n-heptane, n-octane, nonane, decane, dodecane, hexadecane, heptadecane, cyclohexane, perchloroethylene, trichloroethane, and alike may be used as the aliphatic hydrocarbons.
- Nonvolatile organic solvent and organic solvent of relatively low volatility are preferred from the perspective of environmental responsiveness (VOC measures).
- liquid paraffins which include a relatively large amount of aliphatic hydrocarbon with 16 or more carbon atoms may be preferably used.
- Tall oil fatty acid (major components: oleic acid, linoleic acid), vegetable oil-based fatty acid ester, soybean oil, sunflower oil, castor oil, flaxseed oil, and tung oil are exemplified as the vegetable oil.
- the tall oil fatty acid and alike among them are preferably used.
- any carrier liquid C may be used as long as it dissolves the polymer compounds R.
- the one with relatively high solubility for the polymer compounds R (the one which dissolves the polymer compounds R successfully) may be used alone as the carrier liquid C, or it may be combined with the one with relatively low solubility for the polymer compounds R (the one that poorly dissolves the polymer compounds R).
- the electrical conductivity of the entire carrier liquid C (the electrical conductivity of the liquid developer) is adjusted according to types of the carrier liquid C so that the electrical conductivity of the liquid developer does not becomes excessively high.
- vegetable oils such as tall oil fatty acids generally have higher electrical conductivities than the aliphatic hydrocarbons such as liquid paraffins. Therefore, if the aforementioned vegetable oils are included as the carrier liquid C in order to successfully dissolve the polymer compounds R in the carrier liquid C, the electrical conductivities should be carefully adjusted.
- Carrier liquid C which has a greater amount of the aforementioned oil is more advantageous in terms of the solubility for the polymer compounds R whereas it may be disadvantageous in terms of the electrical conductivity.
- Carrier liquid C which has a less amount of the aforementioned oil is more advantageous in terms of the electrical conductivity whereas it may be disadvantageous in terms of the solubility for the polymer compounds R.
- the content of the aforementioned oils in the entire carrier liquid C depends on the type and content of the polymer compounds R contained in the liquid developer, and is preferably, for example, 2 to 80 mass %, and more preferably 5 to 60 mass %. It becomes difficult to successfully dissolve the polymer compounds R in the carrier liquid C if the content of the oils is less than 2 mass %.
- the electrical conductivities of the entire carrier liquid C and the liquid developer become excessively high if the content of the oils exceeds 80 mass %. Excessively high electrical conductivity of the liquid developer leads to low image density.
- the electrical conductivity of the liquid developer is preferably, for example, 200 pS/cm or lower. Therefore, the electrical conductivity of the entire carrier liquid C (the electrical conductivity of the liquid developer) is preferably adjusted to, for example, 200 pS/cm or lower by mixing a highly electrically resistant aliphatic hydrocarbon with resultant solution from dissolving the polymer compounds R in the oils such as tall oil fatty acids (often referred to as “resin solvent” hereinafter).
- Pigment itself may be used as the colored particles P in the present embodiment.
- the liquid developer containing pigment may perform the non-thermal fixation process described in the context of FIGS. 1A to 7 .
- the pigment serving as the colored particles P are fixed onto a recording medium without consuming much thermal energy or optical energy.
- organic pigment or inorganic pigment may be used as the pigments of the present embodiment without any limitation.
- Azine dyes such as carbon black, oil furnace black, channel black, lampblack, acetylene black, and aniline black
- metal salt azo dyes, metallic oxides, and combined metal oxides are exemplified as black pigment.
- Cadmium yellow, mineral fast yellow, nickel titanium yellow, navels yellow, naphthol yellow S, hansa yellow G, hansa yellow 10G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, and tartrazine lake are exemplified as yellow pigment.
- Molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK are exemplified as orange pigment.
- Colcothar, cadmium red, permanent red 4R, lithol red, pyrazolone red, watching red calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, and brilliant carmine 3B are exemplified as red pigment.
- Fast violet B and methyl violet lake are exemplified as purple pigment.
- Pigment Blue 15:3, cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, non-metal phthalocyanine blue, partial chloride of phthalocyanine blue, fast sky blue, and indanthrene blue BC are exemplified as blue pigment.
- Chrome green, chromium oxide, pigment green B, and malachite green lake are exemplified as green pigment.
- the content of each pigment in the liquid developer is preferably 1 to 30 mass %, more preferably 3 mass % or more, and more preferably 5 mass % or more.
- the content of each pigment is also more preferably 20 mass % or less, and more preferably 10 mass % or less.
- An average particle diameter of each pigment in the liquid developer which is a volume basis median diameter (D 50 ), is preferably 0.1 to 1.0 ⁇ m.
- the average particle diameter less than 0.1 ⁇ m leads to, for example, low image density.
- the average particle diameter above 1.0 ⁇ m leads to, for example, low fixation properties.
- the volume basis median diameter (D 50 ) here generally denotes a particle diameter at the point where a cumulative curve based on the total volume 100% of one group of particles with a determined particle distribution attains 50%.
- the liquid developer according to the present embodiment may contain dispersion stabilizer for facilitating and stabilizing dispersion of the particles in the liquid developer.
- Dispersion stabilizer “BYK-116” manufactured by BYK Co., Ltd., for example, may be suitably used as the dispersion stabilizer according to the present embodiment.
- “Solsperse 9000,” “Solsperse 11200,” “Solsperse 13940,” “Solsperse 16000,” “Solsperse 17000, and “Solsperse 18000” manufactured by The Lubrizol Corporation, and “AntaronTM V-216” and “AntaronTM V-220” manufactured by International Specialty Products, Inc. may be preferably used.
- the content of the dispersion stabilizer in the liquid developer is approximately 1 to 10 mass %, and preferably approximately 2 to 6 mass %.
- the polymer compounds R contained in the liquid developer according to the present embodiment are organic polymer compounds such as cyclic olefin copolymer, styrene elastomer, cellulose ether and polyvinyl butyral.
- a material which increases viscosity the liquid developer to prevent bleeding during the image formation may be selected as the organic polymer compounds with high solubility for the carrier liquid C.
- a cyclic olefin copolymer, styrene elastomer, cellulose ether, and polyvinyl butyral are exemplified as the organic polymer compounds.
- styrene elastomer is used as the organic polymer compounds.
- a single type of organic polymer compound or several types of organic polymer compounds may be used as the polymer compounds R.
- the liquid developer of the present embodiment contains the polymer compounds dissolved in the carrier liquid C.
- the organic polymer compounds dissolved in the carrier liquid C may be gel-like polymer compounds. Depending on the types and molecular weights of the organic polymer compounds, the organic polymer compounds are mutually entwined in the carrier liquid C and form gel.
- the gel-like organic polymer compounds have a relatively low fluidity. For example, if concentration of the organic polymer compounds is high or if affinity of the organic polymer compounds for the carrier liquid C is low or if the ambient temperature is low, the organic polymer compounds are likely to form gel. On the other hand, if the organic polymer compounds hardly entwine mutually in the carrier liquid C, solution with a relatively fluidity is obtained.
- the content of the organic polymer compounds in the liquid developer is appropriately determined according to the type of the organic polymer compounds.
- the content of the organic polymer compounds is preferably, for example, 1 to 10 mass %.
- the content of the polymer compounds is less than 1 mass %, sufficient viscosity may not be obtained in the liquid developer, which may ineffectively prevent bleeding during the image formation.
- the content of the polymer compounds exceeding 10 mass % leads to formation of an excessively thick film of the organic polymer compounds on the surface of the sheet S, which significantly deteriorates drying characteristics of the film, increases the adherence (tackiness) of the film, and worsens scratch resistance of the image.
- organic polymer compounds which may be preferably used in the present embodiment are described hereinafter in more detail.
- Cyclic olefin copolymer is amorphous, thermoplastic cyclic olefin resin which has a cyclic olefin skeleton in its main chain without environmental load substance and is excellent in transparency, lightweight properties, and low water absorption properties.
- the cyclic olefin copolymer of the present embodiment is an organic polymer compound with a main chain composed of a carbon-carbon bond, in which at least a part of the main chain has a cyclic hydrocarbon structure.
- the cyclic hydrocarbon structure is introduced by using, as a monomer, a compound having at least one olefinic double bond in the cyclic hydrocarbon structure (cyclic olefin), such as norbornene and tetracyclododecene.
- cyclic olefin such as norbornene and tetracyclododecene.
- Examples of the cyclic olefin copolymer that may be used in the present embodiment include (1) cyclic olefin-based addition (co) polymer or its hydrogenated product, (2) an addition copolymer of a cyclic olefin and an ⁇ -olefin, or its hydrogenated product, and (3) a cyclic olefin-based ring-opening (co) polymer or its hydrogenated product.
- An ⁇ -olefin having 2 to 20 carbon atoms, and preferably 2 to 8 carbon atoms is preferable for the abovementioned ⁇ -olefin.
- Specific examples thereof include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene; 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.
- These ⁇ -olefins may be used alone or in combinations of two or more thereof.
- a method for polymerizing cyclic olefins a method for polymerizing cyclic olefins with a-olefins, and a method for hydrogenating the resultant polymer are not particularly limited and may be carried out according to well-known methods.
- the structure of the cyclic olefin copolymer is not particularly limited and may be linear, branched or crosslinked. In the present embodiment, the cyclic olefin copolymer is preferably linear.
- a copolymer of norbornene and ethylene, or of tetracyclododecene and ethylene may be preferably used as the cyclic olefin copolymer, and the copolymer of norbornene and ethylene is more preferred.
- the content of norbornene in the copolymer is preferably 60 to 82 mass %, more preferably 60 to 79 mass %, yet more preferably 60 to 76 mass %, and most preferably 60 to 65 mass %.
- glass transition temperature of the cyclic olefin copolymer film may become excessively low, which may lead to a risk of lowering film formation properties of the cyclic olefin copolymer. If the content of norbornene exceeds 82 mass %, glass transition temperature of the cyclic olefin copolymer film may become excessively high, which may lead to a risk of lowering fixation properties of the pigments, that is, fixation properties of images by the film of the cyclic olefin copolymer. Or the solubility of the cyclic olefin copolymer for the carrier liquid C may also be reduced.
- a commercially available cyclic olefin copolymer may be used.
- the copolymer of norbornene and ethylene include “TOPASTM TM” (norbornene content: approximately 60 mass %), “TOPASTM TB” (norbornene content: approximately 60 mass %), “TOPASTM 8007” (norbornene content: approximately 65 mass %), “TOPASTM 5013” (norbornene content: approximately 76 mass %), “TOPASTM 6013” (norbornene content: approximately 76 mass %), “TOPASTM 6015” (norbornene content: approximately 79 mass %), and “TOPASTTM 6017” (norbornene content: approximately 82 mass %), which are manufactured by TOPAS Advanced Polymers GmbH. These copolymers may be used alone or in combinations of two or more thereof, depending on the circumstances.
- a conventionally known styrene elastomer may be used as the styrene elastomer available in the present embodiment.
- Specific examples thereof include a block copolymer composed of an aromatic vinyl compound and a conjugated diene compound or olefinic compound.
- Examples of the block copolymer include a block copolymer that has a structure expressed by Chemical Formula where A is a polymer block composed of an aromatic vinyl compound and B is a polymer block composed of an olefinic compound or a conjugated diene compound.
- aromatic vinyl compound constituting the block copolymer examples include styrene, ⁇ -methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,3-dimethylstyrene, 2,4-dimethylstyrene, monochlorostyrene, dichlorostyrene, p-bromostyrene, 2,4,5-tribromostyrene, 2,4,6-tribromostyrene, o-tert-butylstyrene, m-tert-butylstyrene, p-tert-butylstyrene, ethylstyrene, vinylnaphthalene, and vinylanthracene.
- the polymer block A may be composed of one or two or more types of the aforementioned aromatic vinyl compounds.
- the one composed of styrene and/or ⁇ -methylstyrene among these aromatic vinyl compounds provides suitable properties for the liquid developer of the present embodiment.
- Examples of the olefinic compound constituting the block copolymer include ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, cyclopentene, 1-hexene, 2-hexene, cyclohexene, 1-heptene, 2-heptene, cycloheptene, 1-octene, 2-octene, cyclooctene, vinylcyclopentene, vinylcyclohexene, vinylcycloheptene, and vinylcyclooctene.
- Examples of the conjugated diene compound constituting the block copolymer include butadiene, isoprene, chloroprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadien, and 1,3-hexadien.
- the polymer block B may be composed of one or two or more types of each of the olefinic compounds and the conjugated diene compounds.
- the one composed of butadiene and/or isoprene among these compounds provides suitable properties for the liquid developer of the present embodiment.
- block copolymer examples include a polystyrene-polybutadiene-polystyrene triblock copolymer or its hydrogenated product, polystyrene-polyisoprene-polystyrene triblock copolymer or its hydrogenated product, polystyrene-poly (isoprene/butadiene)-polystyrene triblock copolymer or its hydrogenated product, poly ( ⁇ -methylstyrene)-polybutadiene-poly ( ⁇ -methylstyrene) triblock copolymer or its hydrogenated product, poly ( ⁇ -methylstyrene)-polyisoprene-poly ( ⁇ -methylstyrene) triblock copolymer or its hydrogenated product, poly ⁇ -methylstyrene)-poly (isoprene/butadiene)-poly ( ⁇ -methylstyrene) triblock copolymer or its hydrogenated product
- styrene elastomer As the styrene elastomer which may be used in the present embodiment, it is preferred to use a styrene-butadiene elastomer (SBS) that has a structure in which the polymer block A and polymer block B are expressed by Chemical Formula 2.
- SBS styrene-butadiene elastomer
- R 1 , R 2 , R 4 , R 5 and R 6 each represent a hydrogen atom or methyl group
- R 3 represents a hydrogen atom, a halogen atom, a phenyl group or a saturated alkyl group, a methoxy group or ethoxy group having 1 to 20 carbon atoms
- m, n each represent an integer chosen such that the content of the polymer block A ranges from 5 to 75 mass %.
- the styrene-butadiene elastomer is obtained by copolymerizing styrene monomer and butadiene, which is the conjugated diene compound.
- preferred styrene monomer include styrene, ⁇ -methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstirene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-dodecylstyene, p-methoxystyrene, p-phenylstyrene, and p-chlorostyrene.
- the styrene-butadiene elastomer has a number average molecular weight Mn in a range of, preferably, 1,000 to 100,000 (see Chemical Formula 1) and more preferably 2,000 to 50,000, in a molecular weight distribution measured by means of a GPC (gel permeation chromatography).
- a weight-average molecular weight Mw of the styrene-butadiene elastomer is in a range of, preferably, 5,000 to 1,000,000 and more preferably 10,000 to 500,000. In this case, at least one peak is present in the weight-average molecular weight Mw range of 2,000 to 200,000 and preferably in the weight-average molecular weight Mw range of 3,000 to 150,000.
- the value of ratio is preferably equal to or lower than 3.0, and more preferably equal to or lower than 2.0.
- the content of styrene in the styrene-butadiene elastomer is in a range of, preferably, 5 to 75 mass % (see Chemical Formula 2) and more preferably 10 to 65 mass %. If the styrene content is less than 5 mass %, glass transition temperature of the styrene elastomer film becomes excessively low and deteriorates the film formation properties of the styrene elastomer.
- styrene content exceeds 75 mass %, a softening point of the styrene elastomer film becomes excessively high and worsens fixation properties of the pigments, that is, fixation properties of images by the styrene elastomer film.
- styrene elastomer a commercially available styrene elastomer may be used.
- “Klayton” manufactured by Shell “AsapreneTM” T411, T413, T437, “TufpreneTM” A, 315P, which are manufactured by Asahi Kasei Chemicals Corporation, and “JSR TR1086,” “JSR TR2000,” “JSR TR2250” and “JSR TR2827” manufactured by JSR Corporation, may be used as a styrene-conjugated diene block copolymer.
- “Index” manufactured by The Dow Chemical Company may be used as styrene-ethylene copolymer.
- “Aron AR” manufactured by Aronkasei Co., Ltd. and “Rabalon” manufactured by Mitsubishi Chemical Corporation may be used. These materials may be used alone or in combinations of two or more types thereof.
- Cellulose ether is a polymer formed by substituting a hydroxyl group of a cellulose molecule with an alkoxy group.
- the substitution rate is preferably 45 to 49.5%.
- the alkyl moiety of the alkoxy group may be substituted with, for example, hydroxyl group or alike.
- a film formed by cellulose ether is excellent in toughness and thermal stability.
- Examples of the cellulose ether which may be used in the present embodiment include: alkyl cellulose such as methylcellulose and ethylcellulose; hydroxyalkyl cellulose such as hydroxyethyl cellulose and hydroxypropyl cellulose; hydroxy alkyl alkyl cellulose such as hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl ethyl cellulose; carboxy alkyl cellulose such as carboxymethyl cellulose; and carboxy-alkyl hydroxy-alkyl cellulose such as carboxymethyl hydroxyethyl cellulose.
- These cellulose ethers may be used alone or in combinations of two or more thereof. Alkyl celluloses are preferred among these cellulose ethers. Ethyl celluloses are preferred among these alkyl celluloses.
- a commercially available cellulose ether may be used.
- ethylcellulose examples include “EthocelTM STD4,” “EthocelTM STD7,” and “EthocelTM STD10” manufactured by Nissin-Kasei Co., Ltd. These ethyl celluloses may be used alone or in combinations of two or more thereof, depending on the circumstances.
- the polyvinyl butyral which may be used in the present embodiment (butyral resin: alkyl acetalized polyvinyl alcohol) is, as shown in Chemical Formula 3, a copolymer of a hydrophilic vinyl alcohol unit having a hydroxyl group, a hydrophobic vinyl acetal unit having a butyral group, and a vinyl acetate unit having an intermediate property between a vinyl alcohol unit and vinyl acetal unit and having an acetyl group.
- Polyvinyl butyral which has a degree of butyralization (the ratio between a hydrophilic moiety and a hydrophobic moiety) between 60 to 85 mol % is preferred in the liquid developer of the present embodiment in terms of its excellent film formation properties (film formation properties).
- the polyvinyl butyral has a vinyl acetal unit indicating the solubility of the polyvinyl butyral for nonpolar solvent and a vinyl alcohol unit for improving the bonding properties of the recording medium such as a paper sheet. Therefore, the polyvinyl butyral has high affinity with both the carrier liquid C and the recording medium.
- the polyvinyl butyral which may be used in the present embodiment is not particularly limited. Examples thereof include MowitalTM B20H, B30B, B30H, B60T, B60H, B60HH and B70H manufactured by Hoechst AG; “S-LECTM” BL-1 (degree of butyralization: 63 ⁇ 3 mol %), BL-2 (degree of butyralization: 63 ⁇ 3 mol %), BL-S (degree of butyralization: 70 mol % or more), BL-L, BH-3 (degree of butyralization: 65 ⁇ 3 mol %), BM-1 (degree of butyralization: 65 ⁇ 3 mol %), BM-2 (degree of butyralization: 68 ⁇ 3 mol %), BM-5 (degree of butyralization: 63 ⁇ 3 mol %) and BM-S, manufactured by Sekisui Chemical Co., Ltd.; and “Denka butyral” #2000-L, #3000-1, #3000-2,
- the liquid developer according to the present embodiment may be produced by sufficiently dissolving or mixing/dispersing the carrier liquid C, pigments, polymer compounds and optionally the dispersion stabilizer for several minutes to over 10 hours, as appropriate, by using, for example, a ball mill, sand grinder, Dyno mill, rocking mill or alike (or a media distributed machine using zirconia beads and alike may be used).
- the mixing/dispersion time and the rotating speed of the machine are adjusted so that the average particle diameter (D 50 ) of the pigments in the liquid developer becomes, preferably, 0.1 to 1.0 ⁇ m as described above. If the dispersion time is excessively short or if the rotating speed is excessively low, the average particle diameter of the pigments (D 50 ) exceeds 1.0 ⁇ m, and deteriorates the fixation properties as described above. If the dispersion time is excessively long or if the rotating speed is excessively high, the average particle diameter of the pigments (D 50 ) becomes less than 0.1 ⁇ m, which in turn leads to poor developing properties and low image density.
- the liquid developer may be produced by dissolving the polymer compounds in the carrier liquid C and then mixing/dispersing the pigments (along with the dispersion stabilizer, as appropriate).
- the liquid developer may also be produced by preparing solution obtained by dissolving the polymer compounds in the carrier liquid C and a pigment dispersion (obtained by mixing/dispersing the pigments in the carrier liquid C (along with the dispersion stabilizer, as appropriate)), and then mixing the resin solution with the pigment dispersion at an appropriate mixing ratio (mass ratio).
- a particle size distribution needs to be measured in order to calculate the average particle diameter (D 50 ) of the pigments.
- the particle size distribution of the pigments may be measured as follows.
- a given amount of produced liquid developer or prepared pigment dispersion is sampled and diluted to 10 to 100 times of its volume with the same carrier liquid C as the one used in the liquid developer or the pigment dispersion.
- the particle size distribution of thus obtained liquid is measured on the basis of a flow system using a laser diffraction type particle size distribution measuring device “Mastersizer 2000” manufactured by Malvern Instruments Ltd.
- the viscosity of the produced liquid developer may be measured at a measurement temperature of 25° C. by using a vibrational viscometer “Viscomate VM-10A-L” manufactured by CBC Co., Ltd.
- fixation methodologies according to the second embodiment are described hereinafter.
- the fixation methodologies of the second embodiment are associated with effects of a number of rubbing directions on the fixation ratios FR. It should be noted that the fixation methodologies described in the context of the first embodiment is preferably applied to the fixation methodologies of the second embodiment as well. Therefore, some descriptions overlapping with those of the first embodiment are omitted.
- the same reference numerals are used for describing the same elements as those of the first embodiment. The descriptions in the context of the first embodiment are preferably incorporated into the elements which are not described hereinafter.
- FIGS. 11A to 11D are schematic views showing experimental methods, respectively, for investigating effects of a number of rubbing directions on the fixation ratios FR.
- FIGS. 11A to 11D depict experimental conditions according to the present embodiment.
- a sheet S having the image layer I formed thereon was prepared.
- the image layer I is rubbed by the rubbing plate 200 like the experiment described in the context of the first embodiment.
- the image layer I was rubbed under four conditions shown in FIGS. 11A to 11D .
- the other experimental conditions are the same as those described in the context of the first embodiment.
- the image layer I was rubbed in a first experimental direction (from the right to the left). The rubbing was continued for 5 seconds. Meanwhile the image layer I was rubbed 80 times.
- the image layer I was rubbed in the first experimental direction and a second experimental direction (from the left to the right) opposite to the first experimental direction. The rubbing was continued for 5 seconds in total. The image layer I was rubbed 40 times in the first experimental direction and 40 times in the second experimental direction, respectively.
- the image layer I was rubbed in the first experimental direction, the second experimental direction and a third experimental direction (from the bottom to the top) perpendicular to the first and second experimental directions. The rubbing was continued for 5 seconds in total. Meanwhile the image layer I was rubbed 27 times in the first and second experimental directions, respectively, and 26 times in the third experimental direction.
- the image layer I was rubbed in the first experimental direction, the second experimental direction, the third experimental direction and a fourth experimental direction (from the top to the bottom) opposite to the third experimental direction. The rubbing was continued for 5 seconds in total. Meanwhile the image layer I was rubbed 20 times in the first to fourth directions, respectively.
- FIG. 12 is a graph showing fixation ratios FR obtained under the experimental conditions described in the context of FIGS. 11A to 11D .
- the horizontal axis of the graph shown in FIG. 12 represents the number of the rubbing directions described in the context of FIGS. 11A to 11D .
- the vertical axis of the graph shown in FIG. 12 represents the fixation ratios FR of the image layer I on the sheet S.
- the method for calculating the fixation ratios FR shown in FIG. 12 is based on the calculation method described in the context of the first embodiment. The effects of the number of the rubbing directions on the fixation ratios FR are described with reference to FIGS. 11A to 12 .
- the fixation ratio FR linearly went up as an increase in the number of rubbing directions.
- the fixation ratio FR was 56%.
- the fixation ratio FR was 73%.
- the fixation ratio FR was 84%.
- the fixation ratio FR was 94%.
- FIG. 13 is a schematic plan view of a fixing device 300 A configured to perform the three-directional rubbing operations shown in FIG. 11C .
- the fixing device 300 A is described with reference to FIGS. 11A to 11D and 13 .
- the fixing device 300 A comprises the rubbing roller 310 described in the context of the first embodiment.
- the rubbing roller 310 includes the tubular contact cylinder 311 which contacts the image layer I, and the shaft 312 which supports the rotatable contact cylinder 311 .
- the shaft 312 includes a first end 315 and a second end 316 opposite to the first end 315 .
- the fixing device 300 A has a gear 321 mounted on the second end 316 of the shaft 312 , and a motor 330 coupled to the gear 321 .
- the motor 330 rotates the shaft 312 by means of the gear 321 .
- the contact cylinder 311 is integrally rotated with the shaft 312 .
- the fixing device 300 A has a pair of thrust bearings 317 configured to support the rotatable shaft 312 .
- the paired thrust bearings 317 are situated between the first end 315 of the shaft 312 and the contact cylinder 311 as well as between the gear 321 and the contact cylinder 311 .
- the thrust bearings 317 allow the shaft 312 not only to rotate but also to be displaced in an axial direction thereof.
- the fixing device 300 A includes a cam gear 318 which contacts the first end 315 of the shaft 312 , and a motor 319 connected to the cam gear 318 .
- the cam gear 318 eccentrically situated with respect to the shaft 312 includes a circumferential surface 361 engaged with the motor 319 and a pressing surface 362 which contacts the first end 315 of the shaft 312 .
- the pressing surface 362 has a thickness that gradually increases toward the second end 316 of the shaft 312 .
- the vector shown in FIG. 13 exemplifies the first direction D 1 indicating the conveying direction of the sheet S.
- the motor 319 eccentrically rotates the cam gear 318 with respect to the shaft 312 .
- the shaft 312 and the contact cylinder 311 are pressed and displaced in a first traverse direction T 1 perpendicular to the first direction D 1 .
- the cam gear 318 is exemplified as the cam element.
- the fixing device 300 A has a coil spring 363 adjacent to the second end 316 of the shaft 312 .
- the coil spring 363 biases the gear 321 mounted on the second end 316 in a second traverse direction T 2 opposite to the first traverse direction T 1 .
- the motor 319 and the coil spring 363 which reciprocate the contact cylinder 311 in the first and second traverse directions T 1 , T 2 are exemplified as the drive mechanism.
- FIG. 14 shows a reciprocating movement of the rubbing roller 310 caused by the motor 319 .
- the upper drawing of FIG. 14 is a schematic plan view of the fixing device 300 A having the contact cylinder 311 near the cam gear 318 .
- the lower drawing of FIG. 14 is a schematic plan view of the fixing device 300 A having the contact cylinder 311 apart from the cam gear 318 .
- the fixing device 300 A is further described with reference to FIGS. 11A to 11D , 13 and 14 .
- the cam gear 318 is eccentrically situated with respect to the shaft 312 .
- the eccentric amount between the cam gear 318 and the shaft 312 is expressed by an alphabet “e.”
- the contact cylinder 311 approaches the cam gear 318 .
- the contact cylinder 311 moves away from the cam gear 318 .
- the displacement amount of the contact cylinder 311 in the first or second traverse direction T 1 , T 2 is expressed by an alphabet
- the coil spring 363 becomes compressed.
- the first end 315 of the shaft 312 moves on the pressing surface 362 of the cam gear 318 , so that an abutting position between the first end 315 and the pressing surface 362 of the cam gear 318 moves to the thin section of the cam gear 318 , which in turn stretches the coil spring 363 .
- the coil spring 363 appropriately maintains the contact between the first end 315 of the shaft 312 and the cam gear 318 , which appropriately accomplishes the reciprocating movement of the contact cylinder 311 due to the rotation of the cam gear 318 by the motor 319 .
- FIGS. 15A and 15B are schematic side views of the fixing device 300 A and a conveyor which works with the fixing device 300 A to fix the image layer I on the sheet S.
- FIG. 15A entirely shows the fixing device 300 A and the conveyor.
- FIG. 15B is an enlarged view around the rubbing roller 310 .
- the fixing device 300 A is further described with reference to FIGS. 4 , 13 , 15 A and 15 B.
- the conveyor includes an upstream conveyor 410 A disposed before the fixing device 300 A, and a downstream conveyor 420 A disposed after the fixing device 300 A.
- the upstream and downstream conveyors 410 A, 420 A are exemplified as the conveying elements configured to convey the sheet S, like the first embodiment.
- the conveyor comprises an intermediate conveyor 450 situated between the upstream and downstream conveyors 410 A, 420 A.
- the intermediate conveyor 450 is also exemplified as the conveying element.
- the upstream conveyor 410 A comprises the upper and lower rollers 411 , 412 .
- the upstream conveyor 410 A comprises an upper guide plate 461 configured to stably convey the sheet S to the intermediate conveyor 450 , and a lower guide plate 462 situated below the upper guide plate 461 .
- the sheet S conveyed by the upper and lower rollers 411 , 412 is guided by the upper and lower guide plates 461 , 462 and fed to the intermediate conveyor 450 .
- the downstream conveyor 420 A comprises the upper and lower rollers 421 , 422 .
- the downstream conveyor 420 A has an upper guide plate 463 configured to stably convey the sheet S from the intermediate conveyor 450 to a nip portion between the upper and lower rollers 421 , 422 , and a lower guide plate 464 situated below the upper guide plate 463 .
- the sheet S conveyed by the intermediate conveyor 450 is guided by the upper and lower guide plates 463 , 464 and fed to the nip portion between the upper and lower rollers 421 , 422 .
- FIGS. 15A and 15B schematically show the contact cylinder 311 and the shaft 312 of the rubbing roller 310 as the fixing device 300 A.
- the contact cylinder 311 comprises the substantially cylindrical elastic layer 313 which surrounds the circumferential surface of the shaft 312 , and the nonwoven fabric layer 314 which covers the outer circumferential surface of the elastic layer 313 .
- the elastic layer 313 is formed by using, for example, sponge or other soft and elastic material.
- the nonwoven fabric layer 314 is formed by using, for example, any of the nonwoven fabrics described in the context of FIG. 4 .
- the intermediate conveyor 450 includes a drive roller 451 , an idler 452 , and an endless belt 453 extending between the drive roller 451 and the idler 452 .
- the sheet S is sent from the upstream conveyor 410 A onto the endless belt 453 .
- the drive roller 451 revolves the endless belt 453 to convey the sheet S toward the downstream conveyor 420 A.
- the idler 452 is rotated in response to the revolution of the endless belt 453 .
- the directions of the vectors shown in FIGS. 15A and 15B are exemplified as the first direction D 1 indicating the conveying direction of the sheet S, respectively.
- the lengths of the vectors shown in FIGS. 15A and 15B are exemplified as the first speed V 1 indicating the conveying speed for the sheet S, respectively.
- the endless belt 453 is exemplified as the conveying belt.
- the intermediate conveyor 450 has a backup roller 340 A and a cylinder device 350 A connected to the backup roller 340 A.
- the cylinder device 350 A causes the backup roller 340 A to separate from or approach the rubbing roller 310 .
- the cylinder device 350 A is exemplified as the separating/approaching mechanism.
- another mechanism configured to cause the backup roller 340 A to separate from or approach the rubbing roller 310 may be used as the separating/approaching mechanism
- the cylinder device 350 A comprises a shell 353 and a rod 354 which is stored in the shell 353 .
- the rod 354 includes a tip end configured to support the rotatable backup roller 340 A.
- the rod 354 is pushed from the shell 353 by, for example, working fluid (e.g., oil or air) which is fed into the shell 353 .
- working fluid e.g., oil or air
- the backup roller 340 A is displaced toward the rubbing roller 310 .
- the backup roller 340 A displaced toward the rubbing roller 310 pushes the endless belt 453 against the rubbing roller 310 .
- the circumferential surface of the rubbing roller 310 is deformed to form the upper nip surface N 1 along the upper surface of the sheet S passing through the fixing device 300 A, like the first embodiment.
- the outer surface of the endless belt 453 which is deformed along the circumferential surface of the backup roller 340 A, forms the lower nip surface N 2 .
- the upper nip surface N 1 which contacts the image (image layer I) formed on the upper surface of the sheet S is exemplified as the contact surface.
- the sheet S conveyed by the intermediate conveyor 450 passes between the endless belt 453 and the rubbing roller 310 .
- the motor 330 which is described in the context of FIG. 13 , rotates the rubbing roller 310 such that the upper nip surface N 1 moves in the first direction D 1 at the second speed V 2 different from the first speed V 1 .
- the second speed V 2 is greater than the first speed V 1 .
- the second speed V 2 may be lower than the first speed V 1 .
- the rotation of the cam gear 318 reciprocates the upper nip surface N 1 in the first and second traverse directions T 1 , T 2 .
- rubbing the image layer I in the first direction D 1 is accomplished by the speed difference of the upper nip surface N 1 of the sheet S in the first direction D 1 .
- the motor 330 moves the upper nip surface N 1 in the first direction D 1 .
- the motor 330 may move the upper nip surface N 1 in the second direction opposite to the first direction D 1 .
- the motor 330 and the gear 321 may be removed from the fixing device 300 A.
- rubbing the image layer I is accomplished by the reciprocating movement of the contact cylinder 311 in the first and second traverse directions T 1 , T 2 . It is preferred that the shaft 312 supports the rotatable contact cylinder 311 .
- FIG. 16 is a schematic side view of the fixing device 300 A and the conveyor after the sheet S passes through the intermediate conveyor 450 .
- the fixing device 300 A and the conveyor are further described with reference to FIGS. 15A to 16 .
- the upstream conveyor 410 A comprises a switch lever 465 .
- the switch lever 465 includes a turning shaft 466 adjacent to the lower roller 412 , and an arm 467 extending from the turning shaft 466 .
- the arm 467 turns between a reference position (see FIG. 16 ) where the arm 467 traverses a conveyance path PS defined by the upper and lower guide plates 461 , 462 after the nip portion between the upper and lower rollers 411 , 412 , and an inclined position (see FIG. 15A ) where the arm 467 is inclined with respect to the reference position.
- the arm 467 at the reference position is turned to the inclined position by the leading edge of the sheet S sent by the upper and lower rollers 411 , 412 .
- a biasing element (not shown), such as a twisted coil, is mounted on the turning shaft 466 .
- the biasing element biases the switch lever 465 to return the arm 467 to the reference position.
- the switch lever 465 outputs a first trigger signal to a fluid controller (not shown) configured to control flow of the working fluid to the shell 353 of the cylinder device 350 A. Based on the first trigger signal, the fluid controller supplies the working fluid into the shell 353 to extend the rod 354 from the shell 353 . As a result, the backup roller 340 A approaches the rubbing roller 310 . If the arm 467 reaches the reference position, the switch lever 465 outputs a second trigger signal to the fluid controller. Based on the second trigger signal, the fluid controller discharges the working fluid from the shell 353 to retract the rod 354 in the shell 353 . As a result, the backup roller 340 A and the endless belt 453 separate from the rubbing roller 310 , as shown in FIG. 16 . Therefore it is less likely that there are unnecessary rubbing operations between the endless belt 453 and the rubbing roller 310 .
- the fixing device 300 A according to the second embodiment and the conveyor (the upstream, intermediate and downstream conveyor 410 A, 450 , 420 A), which is used for conveying the sheet S to the fixing device 300 A, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor described in the context of the first embodiment.
- FIGS. 17 and 18 are side views schematically showing a fixing device and a conveyor according to the third embodiment, respectively. Different features from those of the second embodiment are described hereinafter. Therefore, some descriptions overlapping with those of the second embodiment are omitted. Hereinafter, the same reference numerals are used for describing the same elements as those of the second embodiment. The descriptions associated with the second embodiment are preferably incorporated into the elements which are not described hereinafter.
- the fixing device and the conveyor according to the third embodiment are described with reference to FIGS. 3 , 17 and 18 .
- the conveyor includes the upstream conveyor 410 A situated before the fixing device 300 A, and the downstream conveyor 420 A situated after the fixing device 300 A.
- the upstream and downstream conveyors 410 A, 420 A are exemplified as the conveying elements configured to convey the sheet S, like the second embodiment.
- the conveyor has an intermediate conveyor 450 B situated between the upstream and downstream conveyors 410 A, 420 A.
- the intermediate conveyor 450 B is also exemplified as the conveying element.
- the intermediate conveyor 450 B includes the drive roller 451 , the idler 452 , and the endless belt 453 extending between the drive roller 451 and the idler 452 .
- the sheet S is sent from the upstream conveyor 410 A onto the endless belt 453 .
- the drive roller 451 revolves the endless belt 453 to convey the sheet S toward the downstream conveyor 420 A.
- the idler 452 is rotated in response to the revolution of the endless belt 453 .
- the intermediate conveyor 450 B comprises an upstream backup roller 343 and a downstream backup roller 344 disposed between the drive roller 451 and the idler 452 .
- the intermediate conveyor 450 B further comprises a frame 349 configured to support the rotatable upstream and downstream backup rollers 343 , 344 .
- the frame 349 moves the endless belt 453 nearby the rubbing roller 310 or separates the endless belt 453 from the rubbing roller 310 by means of the same separating/approaching mechanism as that of the cylinder device 350 A described in the context of the second embodiment.
- the switch lever 465 provided in the upstream conveyor 410 A controls the approaching and separating motions of the endless belt 453 with respect to the rubbing roller 310 .
- the rubbing roller 310 rubs the image layer I on the sheet S in three directions by means of the mechanism described in the context of the second embodiment.
- the upstream and downstream backup rollers 343 , 344 works like the backup roller 340 A described in the context of the second embodiment.
- the intermediate conveyor 450 B comprises an upstream holding roller 345 and a downstream holding roller 346 situated after the rubbing roller 310 .
- the upstream holding roller 345 is disposed in correspondence with the upstream backup roller 343 .
- the downstream holding roller 346 is disposed in correspondence with the downstream backup roller 344 .
- the upstream backup roller 343 pushes the endless belt 453 against the upstream holding roller 345 in response to the movement of the switch lever 465 to the inclined position.
- the downstream backup roller 344 pushes the endless belt 453 against the downstream holding roller 346 in response to the movement of the switch lever 465 to the inclined position.
- the endless belt 453 between the upstream backup roller 343 /upstream holding roller 345 and the downstream backup roller 344 /downstream holding roller 346 is pushed against the circumferential surface of the rubbing roller 310 .
- the rubbing roller 310 defines a travel path of the endless belt 453 curved toward the frame 349 .
- This preferably contributes to higher fixation ratio FR, as described in the context of FIG. 3 .
- the rubbing roller 310 rubs the image layer I on the sheet S
- the sheet S is appropriately held between the upstream backup roller 343 and the upstream holding roller 345 , as well as between the downstream backup roller 344 and the downstream holding roller 346 .
- the rubbing roller 310 also reciprocally rubs the image layer I in the perpendicular direction to the conveying direction of the sheet S. It is likely that conveyance failures of the sheet S, which is caused by the reciprocal rubbing in the perpendicular direction to the conveying direction of the sheet S, are prevented by causing the upstream backup roller 343 , the upstream holding roller 345 , the downstream backup roller 344 and the downstream holding roller 346 to hold the sheet S.
- the sheet S is held by the upstream backup roller 343 , the upstream holding roller 345 , the downstream backup roller 344 and the downstream holding roller 346 .
- the sheet S may be held only between the upstream backup roller 343 and the upstream holding roller 345 .
- the sheet S may be held only between the downstream backup roller 344 and the downstream holding roller 346 .
- FIGS. 19A and 19B schematically show a rubbing roller according to the fourth embodiment.
- FIG. 19A is a schematic cross-sectional view of the rubbing roller.
- FIG. 19B is a schematic plan view of the rubbing roller.
- the rubbing roller according to the fourth embodiment is preferably applied in place of the rubbing roller 310 described in the context of the aforementioned embodiments.
- a rubbing roller 310 C comprises a hard shaft 312 C (e.g., a metallic shaft) and a nonwoven fabric band 314 C spirally wrapped around the circumferential surface of the shaft 312 C.
- the nonwoven fabric band 314 C may be formed, for example, from any of the nonwoven fabrics described in the context of FIG. 4 .
- a backup roller 340 C is formed from a softer elastic material than the shaft 312 C. If the backup roller 340 C is pressed to the shaft 312 C, the backup roller 340 C is elastically deformed to form an appropriate nip portion between the backup and rubbing rollers 340 C, 310 C. Rubbing on the sheet S which passes in between the backup and rubbing rollers 340 C, 310 C is performed on the basis of the fixation methodologies described in the context of the aforementioned embodiments. Thus, the image layer I is preferably fixed on the sheet S.
- FIG. 20 is a schematic view of a fixing device and a conveyor according to the fifth embodiment.
- the fixing device and the conveyor according to the fifth embodiment are described with reference to FIG. 20 .
- the same reference numerals are used for describing the same elements as those of the first embodiment.
- the descriptions associated with the first embodiment are preferably incorporated into the elements which are not described hereinafter.
- a conveyor 400 configured to convey the sheet S with the image layer I thereon comprises a belt unit 450 D, an upstream guider 460 situated before the belt unit 450 D, and a downstream guider 469 situated after the belt unit 450 D.
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 D. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 D:
- the belt unit 450 D comprises the drive roller 451 , the idler 452 , the endless belt 453 extending between the drive roller 451 and the idler 452 , and a tension roller 454 applying tension to the endless belt 453 .
- Rotation of the drive roller 451 causes the endless belt 453 to revolve around the drive roller 451 , the idler 452 and the tension roller 454 .
- the sheet S which is sent from the upstream guider 460 to the outer surface 455 of the endless belt 453 , moves toward the downstream guider 469 in response to the revolution of the endless belt 453 .
- the belt unit 450 D is exemplified as the conveying element.
- the endless belt 453 is exemplified as the conveying belt.
- the belt unit 450 D further comprises a charger 456 configured to charge the outer surface 455 of the endless belt 453 .
- the outer surface 455 of the endless belt 453 which is charged by the charger 456 causes the sheet S to electrostatically stick thereto. Therefore, the sheet S is stably conveyed by the endless belt 453 .
- the endless belt 453 is preferably formed from resin such as PVDF.
- the endless belt 453 includes the inner surface 457 opposite to the outer surface 455 to which the sheet S sticks.
- the belt unit 450 D has a backup roller 340 D which abuts the inner surface 457 of the endless belt 453 .
- the backup roller 340 D includes the upstream and downstream backup rollers 343 , 344 .
- the downstream backup roller 344 is closer to the downstream guider 469 than the upstream backup roller 343 .
- the fixing device 300 D comprises a rubbing roller 310 D configured to rub the image layer I on the sheet S.
- the rubbing roller 310 D includes an upstream rubbing roller 323 corresponding to the upstream backup roller 343 , and a downstream rubbing roller 324 corresponding to the downstream backup roller 344 .
- the downstream rubbing roller 324 rubs the image layer I after the upstream rubbing roller 323 .
- the rubbing roller 310 D is exemplified as the rubbing mechanism.
- the upstream and downstream rubbing rollers 323 , 324 are exemplified as an upstream rubbing mechanism and a downstream rubbing mechanism, respectively.
- the fixing device 300 D comprises a housing 329 configured to partially store the upstream and downstream rubbing rollers 323 , 324 .
- the housing 329 opens toward the endless belt 453 .
- the upstream and downstream rubbing rollers 323 , 324 protrude from the opening of the housing 329 to abut the outer surface 455 of the endless belt 453 or the sheet S.
- the fixing device 300 D comprises a presser 355 configured to press the rubbing roller 310 D against the sheet S.
- the presser 355 includes an upstream coil spring 356 configured to push the upstream rubbing roller 323 against the sheet S, and a downstream coil spring 357 configured to push the downstream rubbing roller 324 against the sheet S.
- the presser 355 may be a cylinder device configured to press the rubbing roller 310 D against the sheet S.
- the upper end of the presser 355 is connected to a top plate 325 of the housing 329 .
- the lower end of the presser 355 is connected to, for example, a bearing (not shown) configured to support a rotatable shaft (not shown) of the rubbing roller 310 D.
- FIG. 21 is a schematic plan view of the fixing device 300 D.
- the fixing device 300 D is further described with reference to FIGS. 20 and 21 .
- the fixing device 300 D includes a drive mechanism 331 mounted on an outer surface of the housing 329 .
- the drive mechanism 331 includes an upstream gear 332 connected to a shaft 326 of the upstream rubbing roller 323 , a downstream gear 333 connected to a shaft 327 of the downstream rubbing roller 324 , an upstream motor 334 connected to the upstream gear 332 , and a downstream motor 335 connected to the downstream gear 333 .
- the upstream motor 334 rotates the upstream rubbing roller 323 on the image layer I.
- the downstream motor 335 rotates the downstream rubbing roller 324 on the image layer I.
- the upstream and downstream motors 334 , 335 are exemplified as the drive mechanisms, respectively.
- the housing 329 and the drive mechanism 331 are configured to allow the rubbing roller 310 D to be displaced as the presser 355 expands or contracts. Thus, the rubbing roller 310 D is appropriately pressed against the image layer I on the sheet S.
- FIG. 22 is a schematic cross-sectional view of the rubbing roller 310 D.
- the rubbing roller 310 D is described with reference to FIGS. 4 and 22 .
- the rubbing roller 310 D comprises a metallic shaft 312 D, an elastic layer 313 D configured to cover the circumferential surface of the shaft 312 D, and a nonwoven fabric layer 314 D configured to cover the circumferential surface of the elastic layer 313 D.
- the nonwoven fabric layer 314 D of the upstream rubbing roller 323 is preferably formed from a material different from the nonwoven fabric layer 314 D of the downstream rubbing roller 324 .
- the upstream rubbing roller 323 may fix the image layer I to the sheet S at a different fixation ratio FR from that of the downstream rubbing roller 324 due to the difference between the materials of the nonwoven fabric layers 314 D, as described in the context of FIG. 4 .
- the circumferential surface of the rubbing roller 310 D includes an elastic circumferential surface.
- FIG. 23 is a schematic cross-sectional view of the upstream and downstream rubbing rollers 323 , 324 which are pressed against the image layer I.
- the rubbing roller 310 D is further described with reference to FIGS. 1A to 1C , 20 , 21 and 23 .
- the upstream coil spring 356 biases the upstream rubbing roller 323 downward with a force F 1 .
- the downstream coil spring 357 biases the downstream rubbing roller 324 downward with a force F 2 greater than the force F 1 . Therefore, the downstream rubbing roller 324 presses the image layer I with a greater force than the upstream rubbing roller 323 .
- a flat upstream nip surface UN along the image layer I is formed on the circumferential surface of the upstream rubbing roller 323 pressed with the force F 1 .
- a flat downstream nip surface DN along the image layer I is formed on the circumferential surface of the downstream rubbing roller 324 pressed with the force F 2 .
- the downstream rubbing roller 324 has the same structure as the upstream rubbing roller 323 . Therefore, the upstream nip surface UN of the upstream rubbing roller 323 , which is pressed by the smaller force F 1 than the force F 2 , is narrower than the downstream nip surface DN of the downstream rubbing roller 324 .
- the elastic layer 313 D of the downstream rubbing roller 324 may be less hard than the elastic layer 313 D of the upstream rubbing roller 323 . In this case, if the force F 2 is equal to or greater than the force F 1 , the area of the downstream nip surface DN is larger than the area of the upstream nip surface UN.
- the elastic layer 313 D of the downstream rubbing roller 324 may be harder than the elastic layer 313 D of the upstream rubbing roller 323 .
- the force F 2 is greater than the force F 1 , it is less likely that an area between the upstream and downstream nip surfaces UN, DN changes. As a result, it is less likely that the rubbing times during which the upstream and downstream rubbing rollers 323 , 324 rub the image layer I changes, which result in facilitating parameter management on the fixation process.
- the upper surface of the colored particles P in the image layer I is covered with the film formed from the polymer compounds R.
- the rubbing operation of the rubbing roller 310 D makes the covering film stronger, so that the image is appropriately protected. In other words, it becomes less likely that the image layer I which is protected by the film layer reinforced by the upstream rubbing roller 323 is damaged as the sheet S is conveyed toward the downstream. Therefore, the pressing force from the upstream rubbing roller 323 (i.e., the force F 1 ) or the area of the upstream nip surface UN is preferably smaller than the pressing force from the downstream rubbing roller 324 (i.e., the force F 2 ) or the area of the downstream nip surface DN.
- the surface pressure of the upstream nip surface UN is set at, for example, 0.02 g/cm 2 .
- the surface pressure of the downstream nip surface DN is set at, for example, 0.20 g/cm 2 .
- the endless belt 453 conveys the sheet S at the first speed V 1 .
- the upstream motor 334 rotates the shaft 312 D such that the upstream nip surface UN, which is exemplified as the contact surface, moves in the conveying direction of the sheet S at the second speed V 2 greater than the first speed V 1 .
- the downstream motor 335 rotates the shaft 312 D such that the downstream nip surface DN, which is exemplified as the contact surface, moves in the conveying direction of the sheet S at the second speed V 2 .
- the rubbing roller 310 D rotates with rubbing the image layer I.
- the first speed V 1 is set at, for example, 300.0 mm/sec.
- the second speed V 2 is set at, for example, 301.5 mm/sec or above.
- FIGS. 24 and 25 show another control method for controlling the rubbing roller 310 D by means of the upstream and downstream motors 334 , 335 (See FIG. 21 ).
- the rubbing roller 310 D is further described with reference to FIGS. 21 , 24 and 25 .
- the upstream motor 334 may rotate the shaft 312 D such that the upstream nip surface UN moves in the conveying direction of the sheet S at the second speed V 2 greater than the first speed V 1 .
- the downstream motor 335 may rotate the shaft 312 D such that the downstream nip surface UN moves in the conveying direction of the sheet S at a third speed V 3 greater than the second speed V 2 .
- the third speed V 3 may be set at, for example, 303.0 mm/sec, while the second speed V 2 is set at 301.5 mm/sec.
- the difference between the third and first speeds V 3 , V 1 is greater than the difference between the second and first speeds V 2 , V 1 .
- the image layer I is rubbed in response to a relatively small speed difference in the upstream.
- the image layer I is rubbed in response to a relatively large speed difference in the downstream.
- the image layer I is fixed at a relatively high fixation ratio FR without excessive damages.
- the upstream motor 334 may rotate the shaft 312 D such that the upstream nip surface UN moves in the conveying direction of the sheet S at the second speed V 2 lower than the first speed V 1 .
- the downstream motor 335 may rotate the shaft 312 D such that the downstream nip surface UN moves in the conveying direction of the sheet S at the third speed V 3 greater than the second speed V 2 .
- upstream motor 334 and the downstream motor 335 may rotate the rubbing roller 310 D to move the upstream and downstream nip surfaces UN, DN, respectively, in an opposite direction to the conveying direction of the sheet S.
- the fixing device 300 D according to the fifth embodiment and the conveyor 400 which conveys the sheet S to the fixing device 300 D are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor that are described in the context of the first embodiment.
- FIG. 26 is a schematic view of a fixing device and a conveyor according to the sixth embodiment. Different features from those of the fifth embodiment are described hereinafter. Therefore, some descriptions overlapping with those of the fifth embodiment are omitted. Hereinafter, the same reference numerals are used for describing the same elements as those of the fifth embodiment. The descriptions associated with the fifth embodiment are preferably incorporated into the elements which are not described hereinafter.
- the fixing device and the conveyor according to the sixth embodiment are described with reference to FIG. 26 .
- a conveyor 400 E configured to convey the sheet S with the image layer I formed thereon has a belt unit 450 E, the upstream guider 460 situated before the belt unit 450 E, and the downstream guider 469 situated after the belt unit 450 E.
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 E. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 E.
- the belt unit 450 E comprises the drive roller 451 , the idler 452 , an endless belt 453 E extending between the drive roller 451 and the idler 452 , and the tension roller 454 applying tension to the endless belt 453 E.
- Rotation of the drive roller 451 causes the endless belt 453 E to revolve around the drive roller 451 , the idler 452 and the tension roller 454 .
- the sheet. S which is sent from the upstream guider 460 to the outer surface 455 of the endless belt 453 E, moves toward the downstream guider 469 in response to the revolution of the endless belt 453 E.
- the belt unit 450 E is exemplified as the conveying element.
- the endless belt 453 E is exemplified as the conveying belt.
- the belt unit 450 E has a vacuum device 456 E. Several through-holes 458 are formed on the endless belt 453 E. While the sheet S is conveyed by the belt unit 450 E, the vacuum device 456 E suctions the sheet S on the endless belt 453 E through the through-holes 458 .
- the endless belt 453 E includes the inner surface 457 opposite to the outer surface 455 to which the sheet S sticks.
- the belt unit 450 E has the backup roller 340 D which abuts the inner surface 457 of the endless belt 453 E.
- the backup roller 340 D includes the upstream and downstream backup rollers 343 , 344 .
- the downstream backup roller 344 is closer to the downstream guider 469 than the upstream backup roller 343 .
- the fixing device 300 E has a rubbing roller 310 E configured to rub the image layer I on the sheet S.
- the rubbing roller 310 E comprises an upstream rubbing roller 323 E corresponding to the upstream backup roller 343 , and a downstream rubbing roller 324 E corresponding to the downstream backup roller 344 .
- the downstream rubbing roller 324 E rubs the image layer I after the upstream rubbing roller 323 E.
- the rubbing roller 310 E is exemplified as the rubbing mechanism.
- the upstream and downstream rubbing rollers 323 E, 324 E are exemplified as the upstream and downstream rubbing mechanisms, respectively.
- the fixing device 300 E comprises the housing 329 configured to partially store the upstream and downstream rubbing rollers 323 E, 324 E.
- the housing 329 opens toward the endless belt 453 E.
- the upstream and downstream rubbing rollers 323 E, 324 E protrude from the opening of the housing 329 to abut the outer surface 455 of the endless belt 453 E or the sheet S.
- the upstream and downstream rubbing rollers 323 E, 324 E are fixedly mounted in the housing 329 . Therefore, the upstream and downstream rubbing rollers 323 E, 324 E may not separate from or approach the endless belt 453 E. It should be noted that the upstream and downstream rubbing rollers 323 E, 324 E are rotated by the same drive mechanism as that of the fifth embodiment.
- FIG. 27 is a schematic cross-sectional view of the upstream and downstream rubbing rollers 323 E, 324 E which rub the image layer I.
- the rubbing roller 310 E is further described with reference to FIGS. 26 and 27 .
- the rubbing roller 310 E comprises the metallic shaft 312 D, a base layer 313 E covering the circumferential surface of the shaft 312 D, and a brush layer 314 E configured by brush 314 e implanted in the base layer 313 E.
- the brush 314 e may be formed from rayon (pile fineness: 300D/100F) or polyester (pile fineness 75D/12F).
- the rubbing roller 310 E includes a circumferential surface having the brush 314 e disposed thereon.
- the brush 314 e is mounted on the shaft 312 D via the base layer 313 E.
- the brush 314 may be directly glued to the shaft 312 D with adhesive.
- the brush 314 e of the upstream rubbing roller 323 E is the same as the brush 314 e of the downstream rubbing roller 324 E.
- the brush 314 e of the upstream rubbing roller 323 E significantly projects from the base layer 313 E, compared to the brush 314 e of the downstream rubbing roller 324 E.
- the diameter of the upstream rubbing roller 323 E is equal to the diameter of the downstream rubbing roller 324 E, and the degree of the projection of the brush 314 e is adjusted on the basis of the thickness of the base layer 313 E.
- a degree of interference between the image layer I and the brush layer 314 E of the upstream rubbing roller 323 E is substantially equal to a degree of interference between the image layer I and the brush layer 314 E of the downstream rubbing roller 324 E.
- the upstream rubbing roller 323 E is rotated at a rotating speed substantially equal to the downstream rubbing roller 324 E.
- the brush 314 e of the upstream rubbing roller 323 E significantly projects from the base layer 313 E, compared to the brush 314 e of the downstream rubbing roller 324 E. Therefore, a load applied to the image layer I by the brush 314 e of the upstream rubbing roller 323 E while the rubbing roller 310 E is rotated, becomes smaller than a load applied to the image layer I by the brush 314 e of the downstream rubbing roller 324 E. Hence, the image layer I is fixed at a relatively high fixation ratio FR without excessive damages.
- the load applied to the image layer by the brush 314 e of the upstream rubbing roller 323 E may be smaller than the load applied to the image layer I by the brush 314 e of the downstream rubbing roller 324 E, in response to the differences in characteristics between, the upstream and downstream rubbing rollers 323 E, 324 E.
- the fixing device 300 E according to the sixth embodiment and the conveyor 400 E which is used for conveying the sheet S to the fixing device 300 E, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 28 is a schematic view of a fixing device and a conveyor according to the seventh embodiment. Different features from those of the fifth embodiment are described hereinafter. Therefore, some descriptions overlapping with those of the fifth embodiment are omitted. Hereinafter, the same reference numerals are used for describing the same elements as those of the fifth embodiment. The descriptions associated with the fifth embodiment are preferably incorporated into the elements which are not described hereinafter.
- the fixing device and the conveyor according to the seventh embodiment are described with reference to FIG. 28 .
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 D. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 D.
- a fixing device 300 F comprises the rubbing roller 310 D configured to rub the image layer I on the sheet S.
- the rubbing roller 310 D comprises the upstream rubbing roller 323 corresponding to the upstream backup roller 343 , and the downstream rubbing roller 324 corresponding to the downstream backup roller 344 .
- the downstream rubbing roller 324 rubs the image layer I after the upstream rubbing roller 323 .
- the fixing device 300 F comprises the housing 329 configured to partially store the upstream and downstream rubbing rollers 323 , 324 .
- the housing 329 opens toward the endless belt 453 .
- the upstream and downstream rubbing rollers 323 , 324 protrude from the opening of the housing 329 to abut the outer surface 455 of the endless belt 453 or the sheet S.
- the fixing device 300 F comprises a cylinder mechanism 370 .
- the cylinder mechanism 370 causes the rubbing roller 310 D to separate from or approach the image layer I of the sheet S on the endless belt 453 .
- the cylinder mechanism 370 is exemplified as a separating/approaching mechanism.
- the separating/approaching mechanism may have another structure configured to cause the rubbing roller 310 D to separate from or approach the endless belt 453 .
- the rubbing roller 310 D may separate from or approach the endless belt 453 by means of a lever arm.
- the cylinder mechanism 370 includes an upstream cylinder device 371 configured to cause the upstream rubbing roller 323 to separate from or approach the image layer I of the sheet S on the endless belt 453 , and a downstream cylinder device 372 configured to cause the downstream rubbing roller 324 to separate from or approach the image layer I of the sheet S on the endless belt 453 .
- the cylinder mechanism 370 includes a shell 353 F configured to receive working fluid, and a rod 354 F stored the shell 353 F.
- the shell 353 F is mounted on the top plate 325 of the housing 329 .
- the rod 354 F of the upstream cylinder device 371 is mounted on the shaft 326 of the upstream rubbing roller 323 .
- the rod 354 F of the downstream cylinder device 372 is mounted on the shaft 327 of the downstream rubbing roller 324 .
- the fixing device 300 F comprises a controller 373 configured to control the cylinder mechanism 370 .
- the controller 373 controls flow of the working fluid to the shell 353 F. If the working fluid flows to the shell 353 F under the control of the controller 373 , the rod 354 F extends from the shell 353 F and pushes the rubbing roller 310 D against the image layer I. If the working fluid flows out from the shell 353 F, the rod 354 F retracts in the shell 353 F, so that the rubbing roller 310 D separates from the image layer I.
- the controller 373 controls the upstream and downstream cylinder devices 371 , 372 independently. Therefore, the controller 373 may push one of the upstream and downstream rubbing rollers 323 , 324 against the image layer I, and separate the other one from the image layer I. Alternatively, the controller 373 may push both the upstream and downstream rubbing rollers 323 , 324 against the image layer I. The controller 373 may separate both the upstream and downstream rubbing rollers 323 , 324 from the image layer I, as appropriate. For example, unless the sheet S is conveyed, the controller 373 may separate the upstream and downstream rubbing rollers 323 , 324 from the image layer I.
- the rubbing roller 310 D may separate from or approach the image layer I in response to passage of the sheet S.
- the rubbing roller 310 D may determine to separate from or approach the image layer I depending on types of liquid developer or the sheet S, which is used for forming the image layer I. For instance, if an image layer I formed by means of liquid developer is likely to be damaged, position of the upstream and/or downstream rubbing rollers 323 , 324 may be controlled such that a degree of interference between the upstream rubbing roller 323 and the endless belt 453 becomes smaller than a degree of interference between the downstream rubbing roller 324 and the endless belt 453 .
- the fixing device 300 F according to the seventh embodiment and the conveyor 400 which is used for conveying the sheet S to the fixing device 300 F, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 29 is a schematic view of a fixing device and a conveyor according to the eighth embodiment.
- the fixing device and the conveyor according to the eighth embodiment are described with reference to FIG. 29 .
- the same reference numerals are used for describing the same elements as those of the aforementioned embodiments.
- the descriptions associated with the aforementioned embodiments are preferably incorporated into the elements which are not described hereinafter.
- a conveyor 400 G configured to convey the sheet S having the image layer I formed thereon comprises a belt unit 450 G, the upstream guider 460 situated before the belt unit 450 G, and the downstream guider 469 situated after the belt unit 450 G.
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 G. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 G.
- the belt unit 450 G comprises the drive roller 451 , the idler 452 , the endless belt 453 extending between the drive roller 451 and the idler 452 , and the tension roller 454 applying tension to the endless belt 453 .
- Rotation of the drive roller 451 causes the endless belt 453 to revolve around the drive roller 451 , the idler 452 and the tension roller 454 .
- the idler 452 and the tension roller 454 rotate in response to the revolution of the endless belt 453 .
- the sheet S which is sent from the upstream guider 460 to the outer surface 455 of the endless belt 453 , moves toward the downstream guider 469 in response to the revolution of the endless belt 453 .
- the sheet S is conveyed from the upstream guider 460 to the downstream guider 469 at the first speed V 1 .
- first direction D 1 the direction from the upstream guider 460 to the downstream guider 469 is referred to as “first direction D 1 ”.
- the belt unit 450 G is exemplified as the conveying element.
- the endless belt 453 is exemplified as the conveying belt.
- the belt unit 450 G further comprises the charger 456 configured to charge the outer surface 455 of the endless belt 453 .
- the outer surface 455 of the endless belt 453 which is charged by the charger 456 , causes the sheet S to electrostatically stick thereto. Therefore, the sheet S is stably conveyed by the endless belt 453 .
- the endless belt 453 is preferably formed from resin such as PVDF.
- the endless belt 453 includes the inner surface 457 opposite to the outer surface 455 to which the sheet S sticks.
- the belt unit 450 G comprises the backup roller 340 which abuts the inner surface 457 of the endless belt 453 .
- the fixing device 300 G comprises a rubbing band 310 G configured to rub the image layer I on the sheet S.
- the rubbing band 310 G is prepared as a nonwoven fabric roll 398 wrapped around a substantially cylindrical core 399 .
- the rubbing band 310 G may be a nonwoven fabric band which is formed by using, for example, any of the nonwoven fabrics described in the context of FIG. 4 .
- the rubbing band 310 G is exemplified as the rubbing belt.
- the fixing device 300 G has an unwinding spindle 397 installed with the nonwoven fabric roll 398 .
- the unwinding spindle 397 is inserted into the core 399 .
- the unwinding spindle 397 preferably includes a chuck mechanism (not shown) configured to hold the core 399 .
- the chuck mechanism stably holds the nonwoven fabric roll 398 on the unwinding spindle 397 .
- the rubbing band 310 G is unwound from the nonwoven fabric roll 398 on the reel spindle 397 .
- the unwinding spindle 397 rotates and unwinds the rubbing band 310 G from the nonwoven fabric roll 398 .
- the unwinding spindle 397 is exemplified as the unwinder.
- the fixing device 300 G has a winding spindle 396 configured to rotate in cooperation with the unwinding spindle 397 .
- the winding spindle 396 is inserted into a substantially cylindrical core 395 .
- the winding spindle 396 comprises a chuck mechanism (not shown) configured to hold the core 395 .
- An end of the rubbing band 310 G which is unwound by the unwinding spindle 397 , is connected to the outer circumferential surface of the core 395 .
- the rubbing band 310 G is wrapped around the core 395 as the winding spindle 396 rotates.
- the winding spindle 396 may wind the rubbing band 310 G.
- the winding spindle 396 is exemplified as the winder.
- the fixing device 300 G has a press mechanism 350 G configured to press the rubbing band 310 G to the image layer I on the sheet S, the rubbing band 310 G extending between the unwinding and winding spindles 397 , 396 .
- the press mechanism 350 G comprises a press roller 351 G provided in correspondence with the backup roller 340 , and a coil spring 352 G configured to bias the press roller 351 G toward the rubbing band 310 G.
- the press mechanism 350 G is exemplified as the first press mechanism.
- the rubbing band 310 G which is unwound by the unwinding spindle 397 , passes between the press roller 351 G and the endless belt 453 , and is then wrapped around the winding spindle 396 .
- the coil spring 352 G configured to bias the press roller 351 G toward the endless belt 453 forms a nip portion N between the rubbing band 310 G and the endless belt 453 to hold the sheet S therebetween.
- the press roller 351 G presses the rubbing band 310 G to the image layer I.
- the coil spring 352 G further biases the press roller 351 G toward the image layer I.
- the press roller 351 G is exemplified as the press piece.
- the coil spring 352 G is exemplified as the biasing element.
- the press roller 351 G comprises a rotating shaft 312 G and a bearing 328 configured to hold the rotating shaft 312 G.
- the press roller 351 G rotates around the rotating shaft 312 G as the rubbing band 310 G moves from the unwinding spindle 397 to the winding spindle 396 .
- a rod or other elements with a surface on which the rubbing band 310 G slides during the movement from the unwinding spindle 397 to the winding spindle 396 may be used as the press piece.
- the coil spring 352 G connected to the bearing 328 is used as the biasing element.
- a cylinder device or other biasing mechanisms configured to bias the press piece toward the image layer I may be used as the biasing element.
- the winding spindle 396 winds the rubbing band 310 G while the endless belt 453 conveys the sheet S.
- the rubbing band 310 G held between the press roller 351 G and the endless belt 453 moves in the first direction D 1 at the second speed V 2 lower than the first speed V 1 while the winding spindle 396 rotates.
- the difference between the conveying speed of the sheet S (the first speed V 1 ) and the winding speed of the winding spindle 396 (the second speed V 2 ) causes rubbing between the image layer I and the rubbing band 310 G.
- the winding spindle 396 , the unwinding spindle 397 and the press mechanism 350 G are exemplified as the sliding mechanisms.
- the fixing device 300 G according to the eighth embodiment and the conveyor 400 G which is used for conveying the sheet S to the fixing device 300 G, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- a fixing device is different from the fixing device 300 G according to the eighth embodiment, in terms of a separator configured to separate the press roller 351 G from the endless belt.
- the separator is described hereinafter. Some descriptions overlapping with those of the eighth embodiment are omitted for clarification.
- the same reference numerals are used for describing the same elements as those of the eighth embodiment.
- the descriptions associated with the eighth embodiment are preferably incorporated into the elements which are not described hereinafter.
- FIGS. 30A and 30B are schematic views of a separator configured to separate the press roller 351 G from the endless belt.
- FIG. 30A shows the press roller 351 G situated in a proximal position near the endless belt.
- FIG. 30B shows the press roller 351 G situated in a separation position away from the endless belt. It should be noted that neither FIGS. 30A nor 30 B shows the rubbing band in order to clarify the separator. The separator is described with reference to FIGS. 30A and 30B .
- a press mechanism 350 H has a separator 380 configured to separate the press roller 351 G from the endless belt 453 E.
- the aforementioned coil spring 352 G includes a first end 358 connected to the bearing 328 which holds the rotating shaft 312 G of the press roller 351 G, and a second end 359 opposite to the first end 358 .
- the separator 380 has a rod arm 381 connected to the second end 359 .
- the press mechanism 350 H is exemplified as the first press mechanism.
- the separator 380 comprises a turning shaft 382 configured to support the rotatable arm 381 .
- the arm 381 includes a base end 383 connected to the turning shaft 382 , and a tip end 384 opposite to the base end 383 .
- the base end 383 of the arm 381 is mounted on the turning shaft 382 via, for example, a twisted coil spring (not shown). The twisted coil spring biases the arm 381 downward. As a result, while the press roller 351 G is present in the proximal position, the coil spring 352 G is compressed to bias the press roller 351 G toward the image layer I on the sheet S.
- the separator 380 comprises a rotating shaft 385 and an eccentric cam piece 386 integrally mounted on the rotating shaft 385 .
- the rotating shaft 385 is rotated by, for example, a solenoid switch (not shown) or other appropriate actuators.
- the eccentric cam piece 386 eccentrically rotates around the rotating shaft 385 to push the tip end 384 of the arm 381 upward.
- the press roller 351 G is moved to the separation position.
- FIGS. 31A and 31B are schematic views of the fixing device and the conveyor according to the ninth embodiment.
- FIG. 31A shows the fixing device and the conveyor during a conveying time period in which the conveyor conveys the sheet S.
- FIG. 31B shows the fixing device and the conveyor during a suspension time period in which the conveyor does not convey the sheet S.
- the fixing device and the conveyor according to the ninth embodiment are described with reference to FIGS. 30A to 31B .
- a conveyor 400 H configured to convey the sheet S having the image layer I formed thereon comprises a belt unit 450 H, the upstream guider 460 situated before the belt unit 450 H, and the downstream guider 469 situated after the belt unit 450 H.
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 H. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 H.
- the belt unit 450 H is stopped, and hence the sheet S is not sent to the conveyor 400 H.
- the belt unit 450 H comprises the drive roller 451 , the idler 452 , the endless belt 453 E extending between the drive roller 451 and the idler 452 , and the tension roller 454 applying tension to the endless belt 453 E.
- Rotation of the drive roller 451 causes the endless belt 453 E to revolve around the drive roller 451 , the idler 452 and the tension roller 454 .
- the idler 452 and the tension roller 454 are rotated as the endless belt 453 E revolves.
- the sheet S which is sent from the upstream guider 460 to the outer surface 455 of the endless belt 453 E, moves toward the downstream guider 469 in response to the revolution of the endless belt 453 E.
- the sheet S is conveyed from the upstream guider 460 to the downstream guider 469 at the first speed V 1 .
- first direction D 1 the direction from the upstream guider 460 to the downstream guider 469 is referred to as “first direction D 1 ”.
- the belt unit 450 H is exemplified as the conveying element.
- the endless belt 453 E is exemplified as the conveying belt.
- the belt unit 450 H comprises the vacuum device 456 E which is disposed along the inner surface 457 opposite to the outer surface 455 of the endless belt 453 E configured to convey the sheet S, and the backup roller 340 .
- Several through-holes 458 are formed on the endless belt 453 E.
- the vacuum device 456 E suctions the sheet S through the through-holes 458 .
- the sheet S which is conveyed by the traveling motion of the endless belt 453 E, sticks to the outer surface 455 of the endless belt 453 E.
- a fixing device 300 H comprises the rubbing band 310 G, the unwinding spindle 397 , and the winding spindle 396 .
- the fixing device 300 H also comprises the press mechanism 350 H described in the context of FIGS. 30A and 30B .
- the arm 381 is partially shown as the separator 380 of the press mechanism 350 H.
- the winding and unwinding spindles 396 , 397 are stopped during the conveying time period.
- the separator 380 keeps the press roller 351 G at the proximal position. Therefore, the rubbing band 310 G and the endless belt 453 E are held between the backup roller 340 and the press roller 351 G.
- the sheet S conveyed by the belt unit 450 H passes through the nip portion N between the rubbing band 310 G and the endless belt 453 E. Meanwhile, the image layer I on the sheet S is rubbed by the rubbing band 310 G.
- the separator 380 moves the press roller 351 G to the separation position, as described in the context of FIGS. 30A and 30B . Meanwhile, the winding spindle 396 winds the rubbing band 310 G which sags as a result of the movement of the press roller 351 G to the separation position.
- the separator 380 moves the press roller 351 G to the proximal position. Meanwhile, the unwinding spindle 397 unwinds the rubbing band 310 G such that the tension added to the rubbing band 310 G becomes constant. Accordingly, when the belt unit 450 H is newly activated, a new section of the rubbing band 310 G rubs the image layer I. As a result, excessive abrasion or contamination of the rubbing band 310 G (e.g., contamination caused by paper dust, oil component, dust and alike on the sheet S). In addition, stopping the rubbing band 310 G during the conveying time period reduces frequency of replacing the rubbing band 310 G.
- FIGS. 32A and 32B show other operations performed by the fixing device 300 H.
- FIG. 32A shows the press roller 351 G at the proximal position.
- FIG. 32B shows the press roller 351 G at the separation position.
- Other operations performed by the fixing device 300 H are described with reference to FIGS. 30A , 30 B, 32 A and 32 B. It should be noted that FIGS. 32A and 32B partially show the arm 381 as the separator 380 of the press mechanism 350 H.
- FIGS. 32A and 32B show a sheet S 1 and a sheet S 2 conveyed after the sheet S 1 .
- the sheet S 1 is exemplified as the preceding sheet.
- the sheet S 2 is exemplified as the subsequent sheet.
- the separator 380 moves the press roller 351 G to the proximal position.
- the separator 380 then keeps the press roller 351 G to the proximal position while the sheet S 1 passes between the press and backup rollers 351 G, 340 . Meanwhile, the rubbing band 310 G rubs the image layer I on the sheet S 1 . It should be noted that the winding and unwinding spindles 396 , 397 are stopped while the press roller 351 G exists in the proximal position.
- the separator 380 moves the press roller 351 G to the separation position. Meanwhile, the winding spindle 396 winds the rubbing band 310 G which sags as a result of the movement of the press roller 351 G to the separation position.
- the separator 380 keeps the press roller 351 G in the separation position until the sheet S 2 starts passing between the press and backup rollers 351 G, 340 .
- the separator 380 moves the press roller 351 G to the proximal position again. While the press roller 351 G is moved to the proximal position, the unwinding spindle 397 unwinds the rubbing band 310 G such that the tension applied to the rubbing band 310 G becomes constant.
- the rubbing band 310 G is wound by the winding spindle 396 and unwound by the unwinding spindle 397 .
- the rubbing band 310 G may be wound by the winding spindle 396 and unwound by the unwinding spindle 310 G.
- the rubbing band 310 G is wound by the winding spindle 396 and unwound by the unwinding spindle 397 , whenever 40 to 50 sheets S pass between the press and backup rollers 351 G, 340 , which result in less replacing frequency of the rubbing band 310 G.
- the fixing device 300 H according to the ninth embodiment and the conveyor 400 H which is used for conveying the sheets S to the fixing device 300 H, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- a fixing device is different from the fixing device 300 G according to the eighth embodiment, in terms of arrangement of the winding and unwinding spindles.
- the differences from the eighth embodiment are described hereinafter. Some descriptions overlapping with those of the eighth embodiment are omitted for clarification.
- the same reference numerals are used for describing the same elements as those of the eighth embodiment.
- the descriptions associated with the eighth embodiment are preferably incorporated into the elements which are not described hereinafter.
- FIG. 33 is a schematic view of a fixing device and a conveyor according to the tenth embodiment. The fixing device and the conveyor according to the tenth embodiment are described with reference to FIG. 33 .
- FIG. 33 shows the same conveyor 400 G as that of the eighth embodiment.
- a fixing device 300 I according to the present embodiment is adjacent to the conveyor 400 G, like the eighth embodiment.
- the fixing device 300 I comprises an unwinding spindle 397 I and a winding spindle 396 I, in addition to the rubbing band 310 G and the press mechanism 350 G of the eighth embodiment.
- the unwinding spindle 397 I is disposed near the downstream guider 469 of the conveyor 400 G.
- the winding spindle 3961 is disposed near the upstream guider 460 of the conveyor 400 G.
- the unwinding spindle 397 I is inserted into the core 399 of the nonwoven fabric roll 398 .
- the unwinding spindle 397 I preferably comprises a chuck mechanism (not shown) configured to hold the core 399 .
- the chuck mechanism stably holds the nonwoven fabric roll 398 on the unwinding spindle 397 I.
- the rubbing band 310 G is unwound from the nonwoven fabric roll 398 on the unwinding spindle 397 I.
- the unwinding spindle 397 I rotates and unwinds the rubbing band 310 G from the nonwoven fabric roll 398 .
- the unwinding spindle 397 I is exemplified as the unwinder.
- the winding spindle 396 I rotates in cooperation with the unwinding spindle 397 I.
- the winding spindle 396 I is inserted into the substantially cylindrical core 395 .
- the winding spindle 396 I comprises a chuck mechanism (not shown) configured to hold the core 395 .
- An end of the rubbing band 310 G which is unwound by the unwinding spindle 397 I is connected to the outer circumferential surface of the core 395 .
- the rubbing band 310 G is wrapped around the core 395 as the winding spindle 396 I rotates.
- the winding spindle 396 I may wind the rubbing band 310 G.
- the winding spindle 396 I is exemplified as the winder.
- the rubbing band 310 G which is unwound by the unwinding spindle 397 I, passes between the press roller 351 G and the endless belt 453 , and is then wrapped around the winding spindle 396 I.
- the coil spring 352 G configured to bias the press roller 351 G toward the endless belt 453 forms a nip portion N between the rubbing band 310 G and the endless belt 453 to hold the sheet S therebetween.
- the press roller 351 G presses the rubbing band 310 G to the image layer I.
- the coil spring 352 G biases the press roller 351 G toward the image layer I.
- the winding spindle 396 I winds the rubbing band 310 G, while the endless belt 453 conveys the sheet S.
- the rubbing band 310 G held between the press roller 351 G and the endless belt 453 moves in the second direction D 2 , while the winding spindle 396 I rotates.
- the difference between the conveying direction of the sheet S (the first direction D 1 ) and the winding direction of the winding spindle 396 I (the second direction D 2 ) causes rubbing between the image layer I and the rubbing band 310 G.
- the winding spindle 396 I, the unwinding spindle 397 I and the press mechanism 350 G are exemplified as the sliding mechanism.
- the fixing device 300 I according to the tenth embodiment and the conveyor 400 G which is used for conveying the sheet S to the fixing device 300 I, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 34 is a schematic view of a fixing device and a conveyor according to the eleventh embodiment.
- Differences from the eighth embodiment are described with reference to FIG. 34 . It should be noted that some descriptions overlapping with those of the eighth embodiment are omitted for clarification. Hereinafter, the same reference numerals are used for describing the same elements as those of the eighth embodiment. The descriptions associated with the eighth embodiment are preferably incorporated into the elements which are not described hereinafter.
- the conveyor 400 configured to convey the sheet S having the image layer I thereon comprises the belt unit 450 D, the upstream guider 460 situated before the belt unit 450 D, and the downstream guider 469 situated after the belt unit 450 D.
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 D. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 D.
- the belt unit 450 D comprises the drive roller 451 , the idler 452 , the endless belt 453 extending between the drive roller 451 and the idler 452 , and the tension roller 454 applying tension to the endless belt 453 .
- Rotation of the drive roller 451 causes the endless belt 453 to revolve around the drive roller 451 , the idler 452 and the tension roller 454 .
- the sheet S which is sent from the upstream guider 460 to the outer surface 455 of the endless belt 453 , moves toward the downstream guider 469 in response to the revolution of the endless belt 453 .
- the belt unit 450 D comprises the charger 456 configured to charge the outer surface 455 of the endless belt 453 , like the eighth embodiment.
- the outer surface 455 of the endless belt 453 which is charged by the charger 456 , causes the sheet S to electrostatically stick thereto.
- the endless belt 453 includes the inner surface 457 opposite to the outer surface 455 to which the sheet S sticks.
- the belt unit 450 D comprises the backup roller 340 D which abuts the inner surface 457 of the endless belt 453 .
- the backup roller 340 D includes the upstream backup roller 343 disposed near the upstream guider 460 , and the downstream backup roller 344 disposed near the downstream guider 469 .
- a fixing device 300 J comprises, like the eighth embodiment, the rubbing band 310 G configured to rub the image layer I on the sheet S, the unwinding spindle 397 configured to unwind the rubbing band 310 G from the nonwoven fabric roll 398 , and the winding spindle 396 configured to wind the rubbing band 310 G, which is unwound by the unwinding spindle 397 .
- the fixing device 300 J comprises a press mechanism 350 J configured to press the rubbing band 310 G to the image layer I.
- the press mechanism 350 J is exemplified as the first press mechanism.
- the press mechanism 350 J includes an intermediate roller 379 situated between the unwinding and winding spindles 397 , 396 .
- the intermediate roller 379 defines a travel path of the rubbing band 310 G so that the rubbing band 310 G separates from the endless belt 453 .
- the intermediate roller 379 is exemplified as the intermediate piece.
- the press mechanism 350 J includes an upstream press roller 323 J, which is provided in correspondence with the upstream backup roller 343 , and a downstream press roller 324 J, which is provided in correspondence with the downstream backup roller 344 .
- the upstream press roller 323 I presses the rubbing band 310 G to the image layer I.
- the downstream press roller 324 I presses the rubbing band 310 G to the image layer I.
- the upstream press roller 323 J is exemplified as the upstream press piece.
- the downstream press roller 324 J is exemplified as the downstream press piece.
- the upstream press roller 323 J comprises a rotating shaft 326 J and a bearing 361 J configured to hold the rotating shaft 326 J.
- the upstream press roller 323 J rotates around the rotating shaft 326 J as the rubbing band 310 G moves from the unwinding spindle 397 to the winding spindle 396 .
- the upstream press roller 324 J comprises a rotating shaft 327 J and a bearing 362 J configured to hold the rotating shaft 327 J.
- the downstream press roller 324 J rotates around the rotating shaft 327 J as the rubbing band 310 G moves from the unwinding spindle 397 to the winding spindle 396 .
- the press mechanism 350 J comprises a separator 380 J configured to separate the upstream and downstream press rollers 323 J, 324 J from the endless belt 453 .
- the separator 380 J comprises an upstream cylinder device 371 J connected to the bearing 361 J of the upstream press roller 323 J.
- the upstream cylinder device 371 J comprises a shell 374 configured to receive working fluid, and a rod 375 which is stored in the shell 374 . A tip end of the rod 375 is connected to the bearing 361 J.
- the upstream cylinder device 371 J may be a commercially available cylinder device.
- the rod 375 retracts in the shell 374 .
- the upstream press roller 323 J connected to the rod 375 moves to a separation position where the upstream press roller 323 J is separated from the endless belt 453 .
- the rod 375 extends from the shell 374 .
- Compressive elasticity of the working fluid in the shell 374 bias the upstream press roller 323 J toward the image layer I on the sheet S conveyed by the endless belt 453 . Therefore, the upstream cylinder device 371 J is also used as the biasing element.
- the separator 380 J comprises a downstream cylinder device 372 J connected to the bearing 362 J of the downstream press roller 324 J.
- the downstream cylinder device 372 J comprises a shell 376 configured to receive the working fluid, and a rod 377 which is stored in the shell 376 . A tip end of the rod 377 is connected to the bearing 362 J.
- the downstream cylinder 372 J may be a commercially available cylinder device.
- the rod 377 retracts in the shell 376 .
- the downstream press roller 324 J connected to the rod 377 moves to a separation position where the downstream press roller 324 J is separated from the endless belt 453 .
- the rod 377 extends from the shell 376 .
- Compressive elasticity of the working fluid in the shell 376 biases the downstream press roller 324 J toward the image layer I on the sheet S conveyed by the endless belt 453 . Therefore, the downstream cylinder device 372 J is also used as the biasing element.
- the separator 380 J comprises a controller 373 J configured to control the upstream and downstream cylinder devices 371 J, 372 J.
- the controller 373 J independently controls the inflow and outflow of the working fluid to and from the shells 374 , 376 . Therefore, the upstream and downstream cylinder devices 371 J, 372 J are independently operated.
- the controller 373 J may control the upstream and/or downstream cylinder devices 371 J, 372 J such that one of the upstream and downstream press rollers 323 J, 324 J is disposed in the separation position away from the endless belt 453 and that the other is disposed in the proximal position near the endless belt 453 .
- the controller 373 J may control the upstream and/or downstream cylinder devices 371 J, 372 J such that one of the upstream and downstream press rollers 323 J, 324 J is disposed in the separation position away from the endless belt 453 and that the other is disposed in the proximal position near the endless belt 453 .
- both the upstream and downstream press rollers 323 J, 324 J may be disposed in the proximal position.
- the image layer I has a low print ratio
- one of the upstream and downstream press rollers 323 J, 324 J may be disposed in the separation position.
- the upstream and/or downstream cylinder devices 371 J, 372 J may be controlled such that the downstream press roller 324 I presses the rubbing band 310 G to the image layer I on the sheet S with a greater force than the upstream press roller 323 J.
- the rubbing band 310 G rubs the image layer I with a weak force in the upstream process where the image layer I is likely to be damaged, and then the rubbing band 310 G rubs the image layer with a strong force in the downstream process. Accordingly, less damage to the image layer I and high fixation ratio FR may be achieved.
- the fixing device 300 J according to the eleventh embodiment and the conveyor 400 which is used for conveying the sheet S to the fixing device 300 J, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 35 is a schematic side view showing a fixing device and a conveyor according to the twelfth embodiment.
- FIG. 36 is a schematic plan view showing the fixing device and the conveyor according to the twelfth embodiment.
- FIG. 37 is a schematic front view showing the fixing device and the conveyor according to the twelfth embodiment.
- the fixing device and the conveyor according to the twelfth embodiment are described with reference to FIGS. 4 and 35 to 37 .
- the same reference numerals are used for describing the same elements as those described in the aforementioned embodiments.
- the descriptions associated with the aforementioned embodiments are preferably incorporated into the elements which are not described hereinafter.
- a conveyor 400 K configured to convey the sheet S having the image layer I formed thereon in the first direction D 1 comprises a substantially tubular backup roller 910 situated under the sheet S, and a substantially tubular nip roller 920 situated above the sheet S.
- the backup roller 910 is connected to a drive source such as a motor (not shown) and rotated to convey the sheet S in the first direction D 1 .
- the nip roller 920 contacts the circumferential surface 911 of the backup roller 910 , and works together with the backup roller 910 to form a nip portion for holding the sheet S therebetween.
- the nip roller 920 rotates in response to the rotation of the backup roller 910 and/or the conveyance of the sheet S.
- the backup roller 910 is exemplified as the conveying element.
- the nip roller 920 is exemplified as the nip element.
- the backup roller 910 extends in a traverse direction T (a direction perpendicular to the conveying direction of the sheet S (the first direction D 1 )), and appropriately supports the sheet S during the conveyance thereof.
- the backup roller 910 comprises a substantially tubular trunk 912 , of which circumferential surface 911 is pressed to the nip roller 920 , and journals 913 which project from the end surfaces of the trunk 912 in the traverse direction T.
- One of the journals 913 is connected to the abovementioned drive source.
- the other rotatable journal 913 is supported, for example, by a bearing mounted to a wall of a housing (not shown) configured to store the conveyor 400 K.
- the nip roller 920 comprises a rotating shaft 921 extending in the traverse direction T, and a substantially tubular rolling piece 922 mounted on the rotating shaft 921 .
- the rolling piece 922 includes a first rolling piece 923 and a second rolling piece 924 .
- the first and second rolling pieces 923 , 924 are aligned in the traverse direction T.
- the rolling piece 922 which is pressed to the circumferential surface 911 of the backup roller 910 , rotates along with the rotating shaft 921 in response to the rotation of the backup roller 910 and/or the conveyance of the sheet S.
- a fixing device 300 K comprises a nonwoven fabric band 310 K configured to rub the image layer I on the sheet S, an unwinding spindle 397 K around which the nonwoven fabric band 310 K is wrapped, and a winding spindle 396 K which winds the nonwoven fabric band 310 K.
- the nonwoven fabric band 310 K may be formed from any of the various nonwoven fabric materials described in the context of FIG. 4 .
- the nonwoven fabric band 310 K is exemplified as the rubbing belt.
- the unwinding spindle 397 K is exemplified as the unwinder.
- the winding spindle 396 K is exemplified as the winder.
- the nonwoven fabric band 310 K is unwound from a nonwoven fabric roll 398 K installed on the unwinding spindle 397 K.
- the nonwoven fabric roll 398 K includes the substantially cylindrical core 399 and the nonwoven fabric band 310 K wrapped around the core 399 .
- the unwinding spindle 397 K is inserted into the core 399 .
- the unwinding spindle 397 K may have, for example, a chuck mechanism (not shown) configured to hold the core 399 .
- the nonwoven fabric band 310 K is unwound from the nonwoven-fabric roll 398 K as the unwinding spindle 397 K rotates.
- the winding spindle 396 K is inserted into the substantially cylindrical core 395 .
- the winding spindle 396 K may include, for example, a chuck mechanism (not shown) configured to hold the core 395 .
- the leading end of the nonwoven fabric band 310 K which is unwound from the nonwoven fabric roll 398 K, is connected to the circumferential surface of the core 395 .
- the nonwoven fabric band 310 K is wrapped around the core 395 as the winding spindle 396 K rotates.
- the nonwoven fabric band 310 K includes a central band 394 passing between the first and second rolling pieces 923 , 924 , a first edge band 389 adjacent to the first rolling piece 923 , and a second edge band 388 adjacent to the second rolling piece 924 .
- the first rolling piece 923 rolls between the first edge band 389 and the central band 394 .
- the second rolling piece 924 rolls between the second edge band 388 and the central band 394 .
- the fixing device 300 K comprises a pressing rod 840 which defines a travel path of the nonwoven fabric band 310 K such that the nonwoven fabric band 310 K contacts the image layer I on the sheet S between the unwinding and winding spindles 397 K, 396 K.
- a rubbing position which is defined by the pressing rod 840 so that the nonwoven fabric band 310 K rubs the image layer I, and a nip portion defined between the nip and backup rollers 920 , 910 , are aligned in the traverse direction T.
- the pressing rod 840 is exemplified as the pressing member.
- the pressing rod 840 includes a curved surface 841 , which is curved to project toward the backup roller 910 .
- the curved surface 841 defines a downwardly curved travel path of the nonwoven fabric band 310 K.
- the nonwoven fabric band 310 K rubs the image layer I on the sheet S between the curved surface 841 and the backup roller 910 .
- the pressing rod 840 extends in the traverse direction T.
- the pressing rod 840 includes a central rod 842 configured to press the central band 394 against the image layer I, a first edge rod 843 configured to press the first edge band 389 against the image layer I, and a second edge rod 844 configured to press the second edge band 388 against the image layer I.
- the first edge rod 843 , the central rod 842 and the second edge rod 844 are aligned in the traverse direction T.
- the first edge rod 843 , the central rod 842 and the second edge rod 844 are situated between the rotating shaft 921 of the nip roller 920 and the backup roller 910 , respectively.
- the fixing device 300 K comprises a connector 850 configured to connect the pressing rod 840 with the rotating shaft 921 of the nip roller 920 .
- the connector 850 comprises a bearing block 851 configured to support the rotating shaft 921 of the nip roller 920 , a rod 852 stored in the bearing block 851 , and a connecting frame 853 which connects a housing (not shown) for storing the fixing device 300 K to the bearing block 851 .
- the connectors 850 correspond to the first edge rod 843 , the central rod 842 , and the second edge rod 844 , respectively.
- the paired rods 852 and the bearing block 851 connected to each rod 852 are disposed on the first edge rod 843 .
- the tip ends of the rods 852 are connected to both ends of the upper surface of the first edge rod 843 , respectively.
- the paired rods 852 and the bearing block 851 connected to each rod 852 are disposed on the central rod 842 .
- the tip ends of the rods 852 are connected to both ends of the upper surface of the central rod 842 , respectively.
- the paired rods 852 and the bearing block 851 connected to each rod 852 are disposed on the second edge rod 844 .
- the tip ends of the rods 852 are connected to both ends of the upper surface of the second edge rod 844 , respectively.
- the connecting frame 853 of the connector 850 which is provided in correspondence with the first edge rod 843 , comprises a connecting plate 854 connected to the upper surfaces of the paired bearing blocks 851 corresponding to the first edge rod 843 , and a connecting arm 855 configured to connect the connecting plate 854 with the abovementioned housing.
- the connecting frame 853 of the connector 850 which is provided in correspondence with the central rod 842 , comprises a connecting plate 854 connected to the upper surfaces of the paired bearing blocks 851 corresponding to the central rod 842 , and a connecting arm 855 configured to connect the connecting plate 854 with the abovementioned housing.
- the connecting frame 853 of the connector 850 which is provided in correspondence with the second edge rod 844 , comprises a connecting plate 854 connected to the upper surfaces of the paired bearing blocks 851 corresponding to the second edge rod 844 , and a connecting arm 855 configured to connect the connecting plate 854 with the abovementioned housing.
- FIG. 38 is a schematic cross-sectional view of the connector 850 .
- the connector 850 is described with reference to FIGS. 35 to 38 .
- Each bearing block 851 comprising an upper portion 856 into which the rotating shaft 921 of the nip roller 920 is inserted, and a hollow lower portion 857 .
- the connector 850 comprises a coil spring 858 buried in the lower portion 857 .
- the rod 852 is inserted into the lower portion 857 .
- the coil spring 858 biases the rod 852 and the pressing rod 840 downward (i.e., toward the backup roller 910 ).
- the pressing rod 840 which is biased toward the backup roller 910 , presses the nonwoven fabric band 310 K against the image layer I on the sheet S.
- the winding spindle 396 K winds the nonwoven fabric band 310 K at a speed different from the conveying speed of the sheet S.
- the difference between the winding speed of the nonwoven fabric band 310 K and the conveying speed of the sheet S makes the image layer I on the sheet S appropriately rubbed.
- the winding spindle 396 K may be stopped. While the nonwoven fabric band 310 K pressed by the pressing rod 840 stops, the sheet S is conveyed by the backup roller 910 in the first direction D 1 , so that the image layer I is appropriately rubbed by the nonwoven fabric band 310 K.
- the unwinding and winding spindles 397 K, 396 K may be arranged such that the travelling direction of the nonwoven fabric band 310 K pressed by the pressing rod 840 becomes opposite to the conveying direction of the sheet S (i.e., the first direction D 1 ).
- the image layer I is appropriately rubbed by the nonwoven fabric band 310 K due to the difference between the conveying direction of the sheet S and the travelling direction of the nonwoven fabric band 310 K.
- FIG. 39 is a schematic side view showing an improved fixing device and conveyor based on the methodologies described with respect to FIGS. 35 to 38 .
- FIG. 40 is a schematic plan view showing the improved fixing device and conveyor. The improved features are described with reference to FIGS. 4 and 38 to 40 . Some descriptions overlapping with those associated with FIGS. 35 and 38 are omitted for clarification. Hereinafter, the same reference numerals are used for describing the same elements as those described in the context of FIGS. 35 to 38 . The descriptions associated with FIGS. 35 to 38 are preferably incorporated into the elements which are not described hereinafter.
- FIGS. 39 and 40 show an auxiliary conveyor 600 and an auxiliary fixing device 500 corresponding to the auxiliary conveyor 600 .
- the auxiliary conveyor 600 is situated before the conveyor 400 K.
- the auxiliary fixing device 500 is situated before the fixing device 300 K. After the auxiliary fixing device 500 rubs the image layer I on the sheet S, the fixing device 300 K rubs the image layer I.
- the auxiliary conveyor 600 conveys the sheet S having the image layer I formed thereon, in the first direction D 1 .
- the auxiliary conveyor 600 has a substantially tubular backup roller 610 disposed under the sheet S, and a substantially tubular nip roller 620 disposed above the sheet S.
- the backup roller 610 is connected to a drive source such as a motor (not shown), and rotated to convey the sheet S in the first direction D 1 .
- the nip roller 620 is pressed to the circumferential surface 611 of the backup roller 610 , and works together with the backup roller 610 to form a nip portion for holding the sheet S therebetween.
- the nip roller 620 rotates in response to the rotation of the backup roller 610 and/or the conveyance of the sheet S.
- the backup roller 610 of the auxiliary conveyor 600 is exemplified as the conveying element, as well as the backup roller 910 of the conveyor 400 K.
- the nip roller 620 of the auxiliary conveyor 600 is exemplified as the nip element, as well as the nip roller 920 of the conveyor 400 K.
- the backup roller 610 of the auxiliary conveyor 600 (c.f. FIG. 39 ) has the same structure as the backup roller 910 of the conveyor 400 K.
- the nip roller 620 of the auxiliary conveyor 600 comprises a rotating shaft 621 extending in the traverse direction T, and a substantially tubular rolling piece 622 mounted on the rotating shaft 621 .
- the rolling piece 622 includes a third rolling piece 623 , a fourth rolling piece 624 , and a fifth rolling piece 625 .
- the third rolling piece 623 is situated in the upstream of the central band 394 of the fixing device 300 K.
- the fourth rolling piece 624 is situated in the upstream of the first edge band 389 .
- the fifth rolling piece 625 is situated in the upstream of the second edge band 388 .
- the third, fourth and fifth rolling pieces 623 , 624 , 625 are aligned in the traverse direction T.
- the rolling piece 622 which is pressed to the circumferential surface 611 of the backup roller 610 , rotates along with the rotating shaft 621 in response to the rotation of the backup roller 610 and/or the conveyance of the sheet S.
- the auxiliary fixing device 500 has a nonwoven fabric band 510 configured to rub the image layer I on the sheet S, an unwinding spindle 520 around which the nonwoven fabric band 510 is wrapped, and a winding spindle 530 configured to wind the nonwoven fabric band 510 .
- the nonwoven fabric band 510 may be formed from any of the various nonwoven fabric materials described in the context of FIG. 4 .
- the nonwoven fabric band 510 of the auxiliary fixing device 500 is exemplified as the rubbing belt, as well as the nonwoven fabric band 310 K of the fixing device 300 K.
- the unwinding spindle 520 of the auxiliary fixing device 500 is exemplified as the unwinder, as well as the unwinding spindle 397 K of the fixing device 300 K.
- the winding spindle 530 of the auxiliary fixing device 500 is exemplified as the winder, as well as the winding spindle 396 K of the fixing device 300 K.
- the nonwoven fabric band 510 is unwound from a nonwoven fabric roll 511 installed on the unwinding spindle 520 .
- the nonwoven fabric roll 511 includes a substantially cylindrical core 512 and the nonwoven fabric band 510 wrapped around the core 512 .
- the unwinding spindle 520 is inserted into the core 512 .
- the unwinding spindle 520 may include, for example, a chuck mechanism (not shown) configured to hold the core 512 .
- the nonwoven fabric band 510 is unwound from the nonwoven fabric roll 511 as the unwinding spindle 520 rotates.
- the winding spindle 530 is inserted into a substantially cylindrical core 513 .
- the winding spindle 530 may include, for example, a chuck mechanism (not shown) configured to hold the core 513 .
- the leading end of the nonwoven fabric band 510 which is unwound from the nonwoven fabric roll 511 , is connected to the circumferential surface of the core 513 .
- the nonwoven fabric band 510 is wrapped around the core 513 as the winding spindle 530 rotates.
- the nonwoven fabric band 510 includes a first auxiliary band 515 passing between the third and fourth rolling pieces 623 , 624 , and a second auxiliary band 516 passing between the third and fifth rolling pieces 623 , 625 .
- the first auxiliary band 515 rubs the image layer I in the upstream of the first rolling piece 923 .
- the second auxiliary band 516 rubs the image layer I in the upstream of the second rolling piece 924 .
- the auxiliary fixing device 500 comprises a pressing rod 540 which defines a travel path of the nonwoven fabric band 510 such that the nonwoven fabric band 510 contacts the image layer I on the sheet S between the unwinding and winding spindles 520 , 530 .
- a rubbing position which is defined by the pressing rod 540 so that the nonwoven fabric band 510 rubs the image layer I, and a nip portion defined between the nip and backup rollers 620 , 610 are aligned in the traverse direction T.
- the pressing rod 540 of the auxiliary fixing device 500 is exemplified as the pressing member, as well as the pressing rod 840 of the fixing device 300 K.
- the pressing rod 540 has a curved surface 541 , which is curved to project toward the backup roller 610 .
- the curved surface 541 defines a downwardly curved travel path of the nonwoven fabric band 510 .
- the nonwoven fabric band 510 rubs the image layer I on the sheet S between the curved surface 541 and the backup roller 610 .
- the pressing rod 540 extends in the traverse direction T.
- the pressing rod 540 includes a first auxiliary rod 543 configured to press the first auxiliary band 515 against the image layer I, and a second auxiliary rod 544 configured to press the second auxiliary band 516 against the image layer I.
- the first and second auxiliary rods 543 , 544 are aligned in the traverse direction T.
- the first and second auxiliary rods 543 , 544 are held between the rotating shaft 621 of the nip roller 620 and the backup roller 610 , respectively, by the connector 850 described in the context of with FIG. 38 .
- the central band 394 of the fixing device 300 K rubs a strip area A 1 extending in the first direction D 1 at substantially the center of the image layer I formed on the sheet S.
- the first edge band 389 of the fixing device 300 K rubs a strip area A 2 extending in the first direction D 1 along one edge of the image layer I.
- the second edge band 388 of the fixing device 300 K rubs a strip area A 3 extending along the other edge opposite to the one edge corresponding to the strip area A 2 .
- the first auxiliary band 515 of the auxiliary fixing device 500 rubs a strip area B 1 between the strip areas A 1 , A 2 .
- the second auxiliary band 516 of the auxiliary fixing device 500 rubs a strip area B 2 between the strip areas A 1 , A 3 .
- the strip area A 1 is not rubbed by the nonwoven fabric band 510 of the auxiliary fixing device 500 . However, the strip area A 1 is appropriately rubbed by the central band 394 of the fixing device 300 K after the image layer I goes through the auxiliary fixing device 500 .
- the fourth rolling piece 624 of the auxiliary conveyor 600 holds a lateral edge SE 1 of the sheet S, which extends in the first direction D 1 . Therefore, the strip area A 2 nearby the lateral edge SE 1 of the sheet S is not rubbed by the nonwoven fabric band 510 of the auxiliary fixing device 500 . However, after the image layer I passes through the auxiliary fixing device 500 , the strip area A 2 is appropriately rubbed by the first edge band 389 of the fixing device 300 K.
- the fifth rolling piece 625 of the auxiliary conveyor 600 holds a lateral edge SE 2 opposite to the lateral edge SE 1 of the sheet S. Therefore, the strip area A 3 nearby the lateral edge SE 2 of the sheet S is not rubbed by the nonwoven fabric band 510 of the auxiliary fixing device 500 . However, after the image layer I passes through the auxiliary fixing device 500 , the strip area A 3 is appropriately rubbed by the second edge band 388 of the fixing device 300 K.
- the strip area B 1 is not rubbed by the nonwoven fabric band 310 K of the fixing device 300 K. However, before the image layer I reaches the fixing device 300 K, the strip area B 1 is appropriately rubbed by the first auxiliary band 515 of the auxiliary fixing device 500 .
- the strip area B 2 is not rubbed by the nonwoven fabric band 310 K of the fixing device 300 K. However, before the image layer I reaches the fixing device 300 K, the strip area B 2 is appropriately rubbed by the second auxiliary band 516 of the auxiliary fixing device 500 .
- the entire image layer I is appropriately rubbed, because the fixing device 300 K rubs the strip areas A 1 , A 2 , A 3 , which are different from the strip areas B 1 , B 2 rubbed by the auxiliary fixing device 500 .
- the first auxiliary band 515 is arranged such that edges of the strip area B 1 preferably overlap with edges of the strip areas A 1 , A 2 .
- the second auxiliary band 516 is arranged such that edges of the strip area B 2 preferably overlap with edges of the strip areas A 1 and A 3 .
- the fixing device 300 K, the auxiliary fixing device 500 , and the conveyor 400 K and the auxiliary conveyor 600 which are used for conveying the sheet S to the fixing device 300 K and the auxiliary fixing device 500 , respectively, according to the present embodiment, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor described in the context of the first embodiment.
- FIG. 41 is a schematic plan view showing a fixing device and a conveyor according to the thirteenth embodiment.
- the differences from the twelfth embodiment are described hereinafter with reference to FIGS. 38 and 41 . Some descriptions overlapping with those of the twelfth embodiment are omitted for clarification.
- the same reference numerals are used for describing the same elements as those of the twelfth embodiment.
- the descriptions associated with the twelfth embodiment are preferably incorporated into the elements which are not described hereinafter.
- FIG. 41 shows a fixing device 300 L corresponding to the conveyor 400 K.
- the fixing device 300 L has the nonwoven fabric band 310 K configured to rub the image layer I on the sheet S, the unwinding spindle 397 K around which the nonwoven fabric band 310 K is wrapped, and the winding spindle 396 K which winds the nonwoven fabric band 310 K.
- the nonwoven fabric band 310 K includes the central band 394 passing between the first and second rolling pieces 923 , 924 , the first edge band 389 adjacent to the first rolling piece 923 , and the second edge band 388 adjacent to the second rolling piece 924 .
- the first rolling piece 923 rolls between the first edge band 389 and the central band 394 .
- the second rolling piece 924 rolls between the second edge band 388 and the central band 394 .
- the fixing device 300 L comprises the pressing rod 840 , which defines a travel path of the nonwoven fabric band 310 K such that the nonwoven fabric band 310 K contacts the image layer I on the sheet S between the unwinding and winding spindles 397 K, 396 K.
- the pressing rod 840 extends in the traverse direction T.
- the pressing rod 840 includes the central rod 842 configured to define a travel path in which the central band 394 is brought into contact with the image layer I on the sheet S, the first edge rod 843 configured to define a travel path in which the first edge band 389 is brought into contact with the image layer I on the sheet S, and the second edge rod 844 configured to define a travel path in which the second edge band 388 is brought into contact with the image layer I on the sheet S.
- the first edge rod 843 , the central rod 842 and the second edge rod 844 are aligned in the traverse direction T.
- the first edge rod 843 , the central rod 842 and the second edge rod 844 are arranged between the rotating shaft 921 of the nip roller 920 and the backup roller 910 , respectively.
- the fixing device 300 L comprises three connectors 850 L connected to the first edge rod 843 , the central rod 842 , and the second edge rod 844 , respectively.
- the connector 850 L connects the pressing rod 840 (the first edge rod 843 , the central rod 842 , and the second edge rod 844 ) and the rotating shaft 921 of the nip roller 920 to each other.
- FIG. 42 is a schematic cross-sectional view of one of the connectors 850 L.
- the connectors 850 L are described with reference to FIGS. 41 and 42 .
- Each connector 850 L has the paired rods 852 connected to the upper surface of the pressing rod 840 , and a bearing block 851 L connected to each rod 852 . Tip ends of the paired rods 852 are connected to both ends of the upper surface of the pressing rod 840 .
- the connector 850 L comprises the connecting frame 853 connected to the paired bearing blocks 851 L.
- the connecting frame 853 comprises the connecting plate 854 connected to the upper end surfaces of the paired bearing blocks 851 , and the connecting arm 855 configured to connect the connecting plate 854 with a housing (not shown) for storing the fixing device 300 L.
- Each bearing block 851 L comprises the upper portion 856 into which the rotating shaft 921 of the nip roller 920 is inserted, and the hollow lower portion 857 L.
- Each rod 852 is inserted into the lower portion 857 L. The rod 852 closes an opening formed in the lower end of the lower portion 857 L.
- a through-hole 891 is formed on a circumferential wall of the lower portion 857 L of each bearing block 851 L.
- the connector 850 L comprises an activation unit 892 , which flows working fluid into and out of the lower portion 857 L of the bearing block 851 L via the through-hole 891 . If the activation unit 892 flows the working fluid into the lower portion 857 L, the pressing rod 840 is displaced downward and approaches the circumferential surface 911 of the backup roller 910 . If the activation unit 892 draws the working fluid from the lower portion 857 L, the pressing rod 840 is displaced upward and separates from the circumferential surface 911 of the backup roller 910 .
- FIG. 43 is a cross-sectional view schematically showing connections among the three connectors 850 L.
- the connectors 850 L are further described with reference to FIGS. 42 and 43 .
- the fixing device 300 L has a controller 893 , which independently control the activation units 892 for causing the central rod 842 to separate from or approach the circumferential surface 911 of the backup roller 910 , the activation unit 892 for causing the first edge rod 843 to separate from or approach the circumferential surface 911 of the backup roller 910 , and the activation unit 892 for causing the second edge rod 844 to separate from or approach the circumferential surface 911 of the backup roller 910 . Under the control of the controller 893 , the central rod 842 , the first edge rod 843 and the second edge rod 844 independently separate from or approach the circumferential surface 911 of the backup roller 910 .
- FIG. 44 is a schematic plan view showing the fixing device and the conveyor.
- FIGS. 45 and 46 are cross-sectional views schematically showing the operations performed by the three connectors 850 L, respectively. The operations of the connectors 850 L are described with reference to FIGS. 41 and 44 to 46 .
- FIGS. 41 , 45 show, as a sheet S, a first sheet SL that is relatively large in the traverse direction T.
- FIGS. 44 , 46 show, as the sheet S, a second sheet SS that is relatively small in the traverse direction T.
- the first sheet SL passes between the central band 394 and the backup roller 910 , between the first edge band 389 and the backup roller 910 , as well as between the second edge band 388 and the backup roller 910 .
- the second sheet SS passes between the central band 394 and the backup roller 910 , but not between the first edge band 389 and the backup roller 910 or between the second edge band 388 and the backup roller 910 .
- each of the three activation units 892 brings the central rod 842 , the first edge rod 843 and the second edge rod 844 close to the circumferential surface 911 of the backup roller 910 under the control of the controller 893 .
- the central band 394 , the first edge band 389 and the second edge band 388 may preferably rub the image layer I.
- the central activation unit 892 brings the central rod 842 close to the circumferential surface 911 of the backup roller 910 under the control of the controller 893 .
- the remaining activation units 892 separate the first and second edge rods 843 , 844 , respectively, from the circumferential surface 911 of the backup roller 910 under the control of the controller 893 .
- the central band 394 rubs the image layer I, but the first and second edge bands 389 , 388 are not rubbed by the circumferential surface 911 of the backup roller 910 to prevent unnecessary abrasion of the first and second edge bands 389 , 388 .
- the nonwoven fabric bands 310 K and 510 are used as the rubbing belts.
- a strip member configured to rub the image layer I may be used as the rubbing belt.
- a strip member having a brush implanted therein may be used as the rubbing belt.
- the fixing device 300 L, the auxiliary fixing device 500 , and the conveyor 400 K and the auxiliary conveyor 600 , which are used for conveying the sheet S to the fixing device 300 L and the auxiliary fixing device 500 , respectively, according to the thirteenth embodiment, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor, which are described in the context of the first embodiment.
- FIG. 47 is a schematic view of a fixing device and a conveyor according to the fourteenth embodiment.
- the fixing device and the conveyor according to the fourteenth embodiment are described with reference to FIGS. 1A to 1C and FIGS. 4 and 47 .
- the same reference numerals are used for describing the same elements as those of the aforementioned embodiments.
- the descriptions associated with the aforementioned embodiments are preferably incorporated into the elements which are not described hereinafter.
- the conveyor 400 G configured to convey the sheet S having the image layer I formed thereon comprises the belt unit 450 G, the upstream guider 460 situated before the belt unit 450 G, and the downstream guider 469 situated after the belt unit 450 G.
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 G. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 G.
- the belt unit 450 G comprises the drive roller 451 , the idler 452 , the endless belt 453 extending between the drive roller 451 and the idler 452 , and the tension roller 454 applying tension to the endless belt 453 .
- Rotation of the drive roller 451 causes the endless belt 453 to revolve around the drive roller 451 , the idler 452 and the tension roller 454 .
- the idler 452 and the tension roller 454 rotate in response to the revolution of the endless belt 453 .
- the endless belt 453 includes the outer surface 455 configured to receive the sheet S from the upstream guider 460 , and the inner surface 457 opposite to the outer surface 455 .
- the inner surface 457 abuts the drive roller 451 , the idler 452 , and the tension roller 454 .
- the sheet S which is sent from the upstream guider 460 to the outer surface 455 of the endless belt 453 , moves toward the downstream guider 469 in response to the revolution of the endless belt 453 .
- the sheet S is conveyed from the upstream guider 460 to the downstream guider 469 at the first speed V 1 .
- first direction D 1 the direction from the upstream guider 460 to the downstream guider 469 is referred to as “first direction D 1 ”.
- the belt unit 450 G is exemplified as the conveying element.
- the endless belt 453 is exemplified as the conveying belt.
- the outer surface 455 of the endless belt 453 is exemplified as the convey
- the belt unit 450 G further comprises the charger 456 configured to charge the outer surface 455 of the endless belt 453 .
- the outer surface 455 of the endless belt 453 which is charged by the charger 456 , causes the sheet S to electrostatically stick thereto. Therefore, the sheet S is stably conveyed by the endless belt 453 .
- the endless belt 453 is preferably formed from resin such as PVDF.
- the belt unit 450 G comprises the backup roller 340 , which abuts the inner surface 457 of the endless belt 453 .
- the backup roller 340 defines a travel path of the endless belt 453 , which is curved and protruded between the drive roller 451 and the idler 452 .
- a fixing device 300 M has a nonwoven fabric band loop 310 M which rubs the image layer I on the sheet S, and a roller mechanism 930 which revolves the nonwoven fabric band loop 310 M.
- the nonwoven fabric band loop 310 M surrounds the roller mechanism 930 .
- the nonwoven fabric band loop 310 M may be formed from, for example, any of the nonwoven fabrics described in the context of FIG. 4 .
- the nonwoven fabric band loop 310 M is exemplified as the rubbing loop.
- the roller mechanism 930 which is used as a drive mechanism for the nonwoven fabric band loop 310 M, is exemplified as the revolving mechanism.
- the roller mechanism 930 has a drive roller 917 configured to revolve the nonwoven fabric band loop 310 M, a tension roller 918 configured to apply tension to the nonwoven fabric band loop 310 M, and a compression portion 990 configured to press the nonwoven fabric band loop 310 M to the image layer I on the sheet S.
- the compression portion 990 includes a first press roller 993 configured to push the nonwoven fabric band loop 310 M to the image layer I, and a second press roller 994 configured to push the nonwoven fabric band loop 310 M to the image layer I after the first press roller 993 .
- the compression portion 990 includes a first coil spring 971 connected to the first press roller 993 , and a second coil spring 972 connected to the second press roller 994 .
- the compression portion 990 is exemplified as the second press mechanism.
- the first and second press rollers 993 , 994 define a travel path of the nonwoven fabric band loop 310 M along the outer surface 455 of the endless belt 453 .
- the backup roller 340 defines a travel path of the endless belt 453 protruding toward the roller mechanism 930 .
- the top of the travel path of the endless belt 453 which is protruded by the backup roller 340 , enters in between the first and second press rollers 993 , 994 . Accordingly, the image layer I on the sheet S keeps in contact with the nonwoven fabric band loop 310 M for relatively long time.
- the first coil spring 971 biases the first press roller 993 toward the endless belt 453 with a biasing force f 1 .
- the second coil spring 972 biases the second press roller 994 toward the endless belt 453 with a biasing force f 2 .
- the biasing force f 2 is preferably greater than the biasing force f 1 .
- the second press roller 994 presses the nonwoven fabric band loop 310 M to the image layer I with a stronger force than the first press roller 993 .
- the drive roller 917 revolves the nonwoven fabric band loop 310 M at the second speed V 2 .
- the nonwoven fabric band loop 310 M between the first and second press rollers 993 , 994 travels in the first direction D 1 at the second speed V 2 .
- the revolution speed of the nonwoven fabric band loop 310 M (the second speed V 2 ) is greater than the conveying speed (the first speed V 1 ) at which the sheet S is conveyed by the belt unit 450 G.
- the drive roller 917 may revolve the nonwoven fabric band loop 310 M at a lower speed than the conveying speed of the sheet S (the first speed V 1 ).
- the drive roller 917 may revolve the nonwoven fabric band loop 310 M such that the nonwoven fabric band loop 310 M between the first and second press rollers 993 , 994 travels in an opposite direction to the conveying direction (the first direction D 1 ) of the sheet S.
- the fixing device 300 M according to the fourteenth embodiment and the conveyor 400 G which is used for conveying the sheet S to the fixing device 300 M, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 48 is a schematic view of a fixing device and a conveyor according to a fifteenth embodiment.
- the differences with the fourteenth embodiment are described hereinafter with reference to FIG. 48 . Some descriptions overlapping with those of the fourteenth embodiment are omitted for clarification.
- the same reference numerals are used for describing the same elements as those of the fourteenth embodiment.
- the descriptions associated with the fourteenth embodiment are preferably incorporated into the elements which are not described hereinafter.
- the conveyor 400 H configured to convey the sheet S having the image layer I formed thereon comprises the belt unit 450 H, the upstream guider 460 situated before the belt unit 450 H, and the downstream guider 469 situated after the belt unit 450 H.
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 H. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 H.
- the belt unit 450 H comprises the drive roller 451 , the idler 452 , the endless belt 453 E extending between the drive roller 451 and the idler 452 , and the tension roller 454 applying tension to the endless belt 453 E.
- Rotation of the drive roller 451 causes the endless belt 453 E to revolve around the drive roller 451 , the idler 452 and the tension roller 454 .
- the idler 452 and the tension roller 454 are rotated as the endless belt 453 E revolves.
- the endless belt 453 E includes the outer surface 455 configured to receive the sheet S from the upstream guider 460 , and the inner surface 457 opposite to the outer surface 455 .
- the inner surface 457 abuts the drive roller 451 , the idler 452 , and the tension roller 454 .
- the sheet S which is sent from the upstream guider 460 to the outer surface 455 of the endless belt 453 E, moves toward the downstream guider 469 in response to the revolution of the endless belt 453 E.
- the sheet S is conveyed from the upstream guider 460 to the downstream guider 469 at the first speed V 1 .
- the belt unit 450 H is exemplified as the conveying element.
- the endless belt 453 E is exemplified as the conveying belt.
- the outer surface 455 of the endless belt 453 E is exemplified as the conveying surface.
- the belt unit 450 H comprises the vacuum device 456 E nearby the inner surface 457 opposite to the outer surface 455 of the endless belt 453 E, which is used as the conveying surface for conveying the sheet S.
- Several through-holes 458 are formed on the endless belt 453 E.
- the vacuum device 456 E suctions the sheet S on the outer surface 455 through the through-holes 458 .
- the endless belt 453 E is preferably formed from resin such as urethane.
- the belt unit 450 H comprises the backup roller 340 , which abuts the inner surface 457 of the endless belt 453 E.
- the backup roller 340 defines a travel path of the endless belt 453 E which is curved and protruded between the drive roller 451 and the idler 452 .
- a fixing device 300 N includes a brush band loop 310 N configured to rub the image layer I on the sheet S, and a roller mechanism 930 N configured to revolve the brush band loop 310 N.
- the brush band loop 310 N includes a strip 311 N surrounding the roller mechanism 930 N, and a brush layer 314 N which includes multiple brushes 314 n implanted in the strip 311 N.
- the brush band loop 310 N is exemplified as the rubbing loop.
- the roller mechanism 930 N comprises the drive roller 917 configured to revolve the brush band loop 310 N, the tension roller 918 configured to apply tension to the brush band loop 310 N, and a compression portion 990 N configured to push the brush band loop 310 N to the image layer I on the sheet S.
- the compression portion 990 N comprises the first press roller 993 configured to push the brush band loop 310 N to the image layer I, and the second press roller 994 configured to push the brush band loop 310 N to the image layer I after the first press roller 993 .
- the strip 311 N of the brush band loop 310 N includes an outer surface 315 N which holds the brushes 314 n , and an inner surface 319 N which contacts the drive roller 917 , the tension roller 918 , the first press roller 993 , and the second press roller 994 .
- the compression portion 990 N defines a rubbing path which extends along the first direction D 1 between the outer surfaces 455 , 315 N of the endless belt 453 E and the strip 311 N.
- the compression portion 990 N defines a distance between the outer surfaces 455 , 315 N of the endless belt 453 E and the strip 311 N in the rubbing path to be shorter than a length of each brush 314 n (the thickness of the brush layer 314 N).
- the brush layer 314 N appropriately rubs the image layer I on the sheet S traveling along the rubbing path.
- the second press roller 994 sets the distance between the outer surfaces 455 , 315 N of the endless belt 453 E and the strip 311 N to be shorter than the distance defined by the first press roller 993 . As a result, the image layer I is rubbed more strongly as the sheet S is conveyed to the downstream.
- the layer of the polymer compounds R which deposit on the surface of the image layer I, becomes hardened over time and increases the scratching resistance. Therefore, rubbing the image layer I with the gradually increasing force may prevent damage to the image layer I and increase the fixation ratio FR of the image layer I to the sheet S.
- the drive roller 917 revolves the brush band loop 310 N at the second speed V 2 .
- the brush band loop 310 N defining the rubbing path travels in the first direction D 1 at the second speed V 2 .
- the revolution speed of the brush band loop 310 N (the second speed V 2 ) is greater than the conveying speed (the first speed V 1 ) at which the sheet S is conveyed by the belt unit 450 H.
- the difference between the revolution speed of the brush band loop 310 N (the second speed V 2 ) and the conveying speed of the sheet S (the first speed V 1 ) makes the image layer I appropriately rubbed by the brush band loop 310 N.
- the drive roller 917 may revolve the brush band loop 310 N at a lower speed than the conveying speed of the sheet S (the first speed V 1 ).
- the drive roller 917 may revolve the brush band loop 310 N such that the brush band loop 310 N defining the rubbing path travels in an opposite direction to the conveying direction of the sheet S (the first direction D 1 ).
- the fixing device 300 N according to the fifteenth embodiment and the conveyor 400 H which is used for conveying the sheet S to the fixing device 300 N, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- a fixing device is different from the fixing device 300 M according to the fourteenth embodiment, in terms of a separating/approaching device configured to cause the compression portion 990 to separate from or approach the endless belt 453 .
- Some descriptions overlapping with those of the fourteenth embodiment are omitted for clarification.
- the same reference numerals are used for describing the same elements as those of the fourteenth embodiment.
- the descriptions associated with the fourteenth embodiment are preferably incorporated into the elements which are not described hereinafter.
- FIGS. 49A and 49B are schematic views of a separating/approaching device configured to separate the compression portion 990 from the endless belt 453 .
- FIG. 49A shows the compression portion 990 situated in a proximal position near the endless belt 453 .
- FIG. 49B shows the first press roller 993 situated in a separation position away from the endless belt 453 , and the second press roller 994 situated in the proximal position. It should be noted that neither FIGS. 49A nor 49 B shows the nonwoven fabric band loop in order to clarify the separating/approaching device.
- FIG. 50 is a schematic view of the fixing device and a conveyor according to the sixteenth embodiment.
- a fixing device 300 P adjacent to the conveyor 400 G configured to convey the sheet S includes the nonwoven fabric band loop 310 M which rubs the image layer I on the sheet S, and a roller mechanism 930 P configured to revolve the nonwoven fabric band loop 310 M.
- the roller mechanism 930 P is exemplified as the revolving mechanism.
- the roller mechanism 930 P comprises the drive roller 917 configured to revolve the nonwoven fabric band loop 310 M, the tension roller 918 configured to apply tension to the nonwoven fabric band loop 310 M, and the compression portion 990 configured to press the nonwoven fabric band loop 310 M to the image layer I on the sheet S.
- the compression portion 990 includes the first press roller 993 configured to press the nonwoven fabric band loop 310 M to the image layer I, and the second press roller 994 configured to press the nonwoven fabric band loop 310 M to the image layer I after the first press roller 993 .
- the compression portion 990 includes the first coil spring 971 connected to the first press roller 993 , and the second coil spring 972 connected to the second press roller 994 .
- the first press roller 993 includes a rotating shaft 926 and a bearing 961 configured to support the rotating shaft 926 .
- the second press roller 994 includes a rotating shaft 927 and a bearing 962 configured to support the rotating shaft 927 .
- the first coil spring 971 includes a first end 956 connected to the bearing 961 , and a second end 957 opposite to the first end 956 .
- the second coil spring 972 includes a first end 958 connected to the bearing 962 , and a second end 959 opposite to the first end 958 .
- the roller mechanism 930 P comprises a separating/approaching device 380 P.
- the separating/approaching device 380 P includes a first separating/approaching device 987 configured to cause the first press roller 993 to separate from or approach the outer surface 455 of the endless belt 453 , and a second separating/approaching device 988 configured to cause the second press roller 994 to separate from or approach the outer surface 455 of the endless belt 453 .
- the first separating/approaching device 987 comprises a rod arm 981 connected to the second end 957 of the first coil spring 971 , and a turning shaft 982 configured to support the rotatable arm 981 .
- the arm 981 includes a base end 983 connected to the turning shaft 982 , and a tip end 984 opposite to the base end 983 .
- the first coil spring 971 is connected to the tip end 984 of the arm 981 .
- the base end 983 of the arm 981 is mounted on the turning shaft 982 via, for example, a twisted coil spring (not shown).
- the twisted coil spring biases the tip end 984 of the arm 981 toward the outer surface 455 of the endless belt 453 .
- the compressed first coil spring 971 biases the first press roller 993 toward the image layer I on the sheet S.
- the first separating/approaching device 987 comprises a rotating shaft 985 and an eccentric cam piece 986 integrally mounted on the rotating shaft 985 .
- the rotating shaft 985 is rotated by, for example, a first actuator 989 such as a solenoid switch (not shown).
- a first actuator 989 such as a solenoid switch (not shown).
- the eccentric cam piece 986 eccentrically rotates around the rotating shaft 985 to separate the tip end 984 of the arm 981 from the endless belt 453 . Consequently, the first press roller 993 is moved to the separation position.
- the second separating/approaching device 998 comprises a rod arm 991 connected to the second end 959 of the second coil spring 972 , and a turning shaft 992 configured to support the rotatable arm 991 .
- the arm 991 includes a base end 973 connected to the turning shaft 992 , and a tip end 974 opposite to the base end 973 .
- the second coil spring 972 is connected to the tip end 974 of the arm 991 .
- the base end 973 of the arm 991 is mounted on the turning shaft 992 via, for example, a twisted coil spring (not shown).
- the twisted coil spring biases the tip end 974 of the arm 991 toward the outer surface 455 of the endless belt 453 .
- the compressed second coil spring 972 biases the second press roller 994 toward the image layer I on the sheet S.
- the second separating/approaching device 988 comprises a rotating shaft 975 and an eccentric cam piece 976 integrally mounted on the rotating shaft 975 .
- the rotating shaft 975 is rotated by, for example, a second actuator 979 such as a solenoid switch (not shown).
- a second actuator 979 such as a solenoid switch (not shown).
- the eccentric cam piece 976 eccentrically rotates around the rotating shaft 975 to separate the tip end 974 of the arm 991 from the endless belt 453 . Consequently, the second press roller 994 is moved to the separation position.
- the roller mechanism 930 P has a controller 373 P configured to independently control the first and second separating/approaching devices 987 , 988 .
- the first and second separating/approaching devices 987 , 988 independently causes the first and second press rollers 993 , 994 to separate from or approach the outer surface 455 of the endless belt 453 . Therefore, a length of the rubbing path extending in the first direction D 1 is adjusted under the control of the controller 373 P.
- the controller 373 P may cause the first or second press roller 993 , 994 to separate from or approach the outer surface 455 of the endless belt 453 , for example, in response to the print ratio of the image layer I. For instance, if the print ratio of the image layer I is relatively low, the controller 373 P may separate the first press roller 993 from the outer surface 455 of the endless belt 453 and keep the second press roller 994 at the proximal position. If the print ratio of the image layer I is relatively high, the controller 373 P may keep both the first and second press rollers 993 , 994 at the proximal position.
- FIGS. 51A and 51B schematically show the operations performed by the separating/approaching device 380 P.
- FIG. 51A schematically shows the separating/approaching device 380 P which keeps the first and second press rollers 993 , 994 at the proximal position.
- FIG. 51B schematically shows the separating/approaching device which displaces the first and second press rollers 993 , 994 to the separation position.
- the operations of the separating/approaching device 380 P are described with reference to FIGS. 50 to 51B .
- the sheets S are sequentially sent from the upstream guider 460 to the belt unit 450 G.
- the sheets S which electrostatically stick to the outer surface 455 of the endless belt 453 charged by the charger 456 , are sequentially conveyed toward the downstream guider 469 .
- FIGS. 51A and 51B show the sheet S 1 and the sheet S 2 following the sheet S 1 , as the sheets S.
- Each sheet S includes a leading edge LE which first enters into the rubbing path and a trailing edge TE opposite to the leading edge LE.
- the leading edge LE of the sheet S 2 is away from the trailing edge TE of the preceding sheet S 1 .
- the conveyance of the sheets S shown in FIGS. 51A and 51B is adopted in various image forming apparatuses such as copy machines, printers, facsimile devices, and combined machines.
- the sheets S 1 and S 2 are conveyed by the endless belt 453 in the first direction D 1 at the first speed V 1 .
- the controller 373 P controls the first and second actuators 989 , 979 so that the first and second press rollers 993 , 994 approach the outer surface 455 of the endless belt 453 , the rubbing path extending in the first direction D 1 is defined between the nonwoven fabric band loop 310 M and the outer surface 455 of the endless belt 453 . While each sheet S passes through the rubbing path, the image layer I is rubbed by the nonwoven fabric band loop 310 M.
- the controller 373 P controls the first and second actuators 989 , 979 to displace the first and second press rollers 993 , 994 to the separation position away from the outer surface 455 of the endless belt 453 . Subsequently, immediately before the sheet S 2 passes between the first press roller 993 and the endless belt 453 , the controller 373 P controls the first and second actuators 989 , 979 so that the first and second press rollers 993 , 994 approach the outer surface 455 of the endless belt 453 . As a result, the rubbing path is defined. Therefore, it is less likely that the nonwoven fabric band loop 310 M and the endless belt 453 rub each other between the sheet S 1 and the sheet S 2 .
- the fixing device 300 P according to the sixteenth embodiment and the conveyor 400 G which is used for conveying the sheet S to the fixing device 300 P, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 52 is a schematic view of a fixing device and a conveyor according to the seventeenth embodiment.
- the differences from the fourteenth embodiment are described hereinafter with reference to FIGS. 1A to 1C and FIGS. 4 and 52 .
- Some descriptions overlapping with those of the fourteenth embodiment are omitted for Clarification.
- the same reference numerals are used for describing the same elements as those of the fourteenth embodiment.
- the descriptions associated with the fourteenth embodiment are preferably incorporated into the elements which are not described hereinafter.
- the conveyor 400 configured to convey the sheet S having the image layer I formed thereon comprises the belt unit 450 D, the upstream guider 460 situated before the belt unit 450 D, and the downstream guider 469 situated after the belt unit 450 D.
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 D. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 D.
- the belt unit 450 D comprises the drive roller 451 , the idler 452 , the endless belt 453 extending between the drive roller 451 and the idler 452 , and the tension roller 454 applying tension to the endless belt 453 .
- Rotation of the drive roller 451 causes the endless belt 453 to revolve around the drive roller 451 , the idler 452 and the tension roller 454 .
- the idler 452 and the tension roller 454 are rotated as the endless belt 453 revolves.
- the endless belt 453 includes the outer surface 455 configured to receive the sheet S from the upstream guider 460 , and the inner surface 457 opposite to the outer surface 455 .
- the inner surface 457 abuts the drive roller 451 , the idler 452 , and the tension roller 454 .
- the sheet S which is sent from the upstream guider 460 to the outer surface 455 of the endless belt 453 , moves toward the downstream guider 469 in response to the revolution of the endless belt 453 .
- the sheet S is conveyed from the upstream guider 460 to the downstream guider 469 at the first speed V 1 .
- the belt unit 450 D further comprises the charger 456 configured to charge the outer surface 455 of the endless belt 453 .
- the sheet S electrostatically sticks to the outer surface 455 of the endless belt 453 charged by the charger 456 . Therefore, the sheet S is stably conveyed by the endless belt 453 .
- the belt unit 450 D comprises the backup roller 340 D, which abuts the inner surface 457 of the endless belt 453 .
- the backup roller 340 D includes the upstream backup roller 343 nearby the idler 452 , and the downstream backup roller 344 near the drive roller 451 .
- a fixing device 300 Q includes an upstream fixing device 301 corresponding to the upstream backup roller 343 , and a downstream fixing device 302 corresponding to the downstream backup roller 344 .
- the upstream fixing device 301 first rubs the image layer I on the sheet S, which has sent from the upstream guider 460 to the endless belt 453 . Subsequently, the downstream fixing device 302 rubs the image layer I. This increases the rubbing time for rubbing the image layer I.
- the upstream fixing device 301 includes an upstream nonwoven fabric band loop 1510 configured to rub the image layer I on the sheet S, and an upstream roller mechanism 1530 configured to revolve the upstream nonwoven fabric band loop 1510 .
- the upstream nonwoven fabric band loop 1510 surrounds the upstream roller mechanism 1530 .
- the upstream nonwoven fabric band loop 1510 may be formed from any of the nonwoven fabrics described in the context of FIG. 4 .
- the upstream roller mechanism 1530 comprises a drive roller 1517 configured to revolve the upstream nonwoven fabric band loop 1510 , a tension roller 1518 configured to apply tension to the upstream nonwoven fabric band loop 1510 , and an upstream compression portion 1520 configured to press the upstream nonwoven fabric band loop 1510 to the image layer I on the sheet S.
- the upstream compression portion 1520 comprises a first press roller 1523 configured to press the upstream nonwoven fabric band loop 1510 to the image layer I, and a second press roller 1524 configured to press the upstream nonwoven fabric band loop 1510 to the image layer I after the first press roller 1523 .
- the upstream compression portion 1520 comprises a first coil spring 1571 connected to the first press roller 1523 , and a second coil spring 1572 connected to the second press roller 1524 .
- the first and second press rollers 1523 , 1524 define a travel path of the upstream nonwoven fabric band loop 1510 along the outer surface 455 of the endless belt 453 .
- the upstream backup roller 343 defines a travel path of the endless belt 453 protruding toward the upstream roller mechanism 1530 .
- the top of the travel path of the endless belt 453 which is protruded by the upstream backup roller 343 , enters between the first and second press rollers 1523 , 1524 . Accordingly, the image layer I on the sheet S keeps in contact with the upstream nonwoven fabric band loop 1510 for relatively long time.
- the downstream fixing device 302 includes a downstream nonwoven fabric band loop 1610 configured to rub the image layer I on the sheet S, and a downstream roller mechanism 1630 configured to revolve the downstream nonwoven fabric band loop 1610 .
- the downstream nonwoven fabric band loop 1610 surrounds the downstream roller mechanism 1630 .
- the downstream nonwoven fabric band loop 1610 may be formed from, for example, any of the nonwoven fabrics described in the context of FIG. 4 .
- the downstream roller mechanism 1630 comprises a drive roller 1617 configured to revolve the downstream nonwoven fabric band loop 1610 , a tension roller 1618 configured to apply tension to the downstream nonwoven fabric band loop 1610 , and a downstream compression portion 1620 configured to press the downstream nonwoven fabric band loop 1610 to the image layer I on the sheet S.
- the downstream compression portion 1620 comprises a third press roller 1623 configured to press the downstream nonwoven fabric band loop 1610 to the image layer I, and a fourth press roller 1624 configured to press the downstream nonwoven fabric band loop 1610 to the image layer I after the third press roller 1623 .
- the downstream compression portion 1620 comprises a third coil spring 1671 connected to the third press roller 1623 , and a fourth coil spring 1672 connected to the fourth press roller 1624 .
- the third and fourth press rollers 1623 , 1624 define a travel path of the downstream nonwoven fabric band loop 1610 along the outer surface 455 of the endless belt 453 .
- the downstream backup roller 344 defines a travel path of the endless belt 453 protruding toward the downstream roller mechanism 1630 .
- the top of the travel path of the endless belt 453 which is protruded by the downstream backup roller 344 , enters between the third and fourth press rollers 1623 , 1624 . Accordingly, the image layer I on the sheet S keeps in contact with the downstream nonwoven fabric band loop 1610 for relatively long time.
- the first coil spring 1571 biases the first press roller 1523 toward the endless belt 453 with the biasing force f 1 .
- the second coil spring 1572 biases the second press roller 1524 toward the endless belt 453 with the biasing force f 2 .
- the biasing force f 2 is preferably greater than the biasing force f 1 .
- the second press roller 1524 presses the upstream nonwoven fabric band loop 1510 to the image layer I with a stronger force than the first press roller 1523 .
- the third coil spring 1671 biases the third press roller 1623 toward the endless belt 453 with a biasing force f 3 .
- the fourth coil spring 1672 biases the fourth press roller 1624 toward the endless belt 453 with a biasing force f 4 .
- the biasing force f 4 is preferably greater than the biasing force f 3 .
- the fourth press roller 1624 presses the downstream nonwoven fabric band loop 1610 to the image layer I with a stronger force than the third press roller 1623 .
- a total force of the biasing forces f 3 , f 4 is preferably greater than a total force of the biasing forces f 1 , f 2 .
- the layer of the polymer compounds R, which deposit on the surface of the image layer I becomes hardened over time and increases scratching resistance. Therefore, rubbing the image layer I by means of the upstream nonwoven fabric band loop 1510 under a relatively low pressing force in the upstream and rubbing the image layer I by means of the downstream nonwoven fabric band loop 1610 under a relatively high pressing force in the downstream may prevent damage to the image layer I and increase the fixation ratio FR of the image layer I to the sheet S.
- the drive roller 1517 of the upstream roller mechanism 1530 revolves the upstream nonwoven fabric band loop 1510 at the second speed V 2 .
- the upstream nonwoven fabric band loop 1510 between the first and second press rollers 1523 , 1524 travels in the first direction D 1 at the second speed V 2 .
- the revolution speed of the upstream nonwoven fabric band loop 1510 (the second speed V 2 ) is greater than the conveying speed (the first speed V 1 ) at which the sheet S is conveyed by the belt unit 450 D.
- the difference between the revolution speed of the upstream nonwoven fabric band loop 1510 (the second speed V 2 ) and the conveying speed (the first speed V 1 ) of the sheet S makes the image layer I appropriately rubbed by the upstream nonwoven fabric band loop 1510 .
- the drive roller 1617 of the downstream roller mechanism 1630 revolves the downstream nonwoven fabric band loop 1610 at the third speed V 3 .
- the downstream nonwoven fabric band loop 1610 between the third and fourth press rollers 1623 , 1624 travels in the first direction D 1 at the third speed V 3 .
- the revolution speed of the downstream nonwoven fabric band loop 1610 (the third speed V 3 ) is greater than the revolution speed of the upstream nonwoven fabric band loop 1510 (the second speed V 2 ).
- the image layer I is rubbed more by the downstream nonwoven fabric band loop 1610 than the upstream nonwoven fabric band loop 1510 .
- the fixing device 300 Q according to the seventeenth embodiment and the conveyor 400 which is used for conveying the sheet S to the fixing device 300 Q, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 53 is a schematic view of a fixing device 750 and conveyor 400 G according to the eighteenth embodiment.
- the fixing device 750 and the conveyor 400 G according to the eighteenth embodiment are described with reference to FIG. 53 .
- the same reference numerals are used for describing the same elements as those of the aforementioned embodiments.
- the descriptions associated with the aforementioned embodiments are preferably incorporated into the elements which are not described hereinafter.
- the sheet S having the image layer I formed thereon is conveyed to the fixing device 750 by the conveyor 400 G.
- the conveyor 400 G comprises the belt unit 450 G, the upstream guider 460 situated before the belt unit 450 G, and the downstream guider 469 situated after the belt unit 450 G.
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 G. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 G.
- the surface of the sheet S, on which the image layer I is formed is exemplified as the formation surface.
- the belt unit 450 G comprises the drive roller 451 , the idler 452 , the endless belt 453 extending between the drive roller 451 and the idler 452 , and the tension roller 454 applying tension to the endless belt 453 .
- Rotation of the drive roller 451 causes the endless belt 453 to revolve around the drive roller 451 , the idler 452 and the tension roller 454 .
- the idler 452 and the tension roller 454 rotate in response to the revolution of the endless belt 453 .
- the sheet S which is sent from the upstream guider 460 to the endless belt 453 , moves toward the downstream guider 469 in response to the revolution of the endless belt 453 .
- the sheet S is conveyed from the upstream guider 460 to the downstream guider 469 at the first speed V 1 .
- Reference numeral D 1 represents the direction in which the sheet S is moved from the upstream guider 460 toward the downstream guider 469 by the belt unit 450 G.
- the belt unit 450 G is exemplified as the conveying element.
- the belt unit 450 G further comprises the backup roller 340 arranged inside the endless belt 453 .
- the backup roller 340 abuts with the inner surface of the endless belt 453 at a position between the drive roller 451 and the idler 452 , which is situated on the opposite side to the tension roller 454 .
- the fixing device 750 rubs and fixes the image layer I on the sheet S.
- the fixing device 750 includes a rubbing member 751 situated on the opposite side of the backup roller 340 so that the endless belt 453 intervenes between the rubbing member 751 and the backup roller 340 , and a drive source 752 configured to drive the rubbing member 751 .
- the rubbing member 751 includes a supporting member 753 , a nonwoven fabric layer 754 , and a shaft 755 .
- FIG. 54 is a perspective view of the rubbing member 751 .
- the supporting member 753 is a cylindrical block member.
- the supporting member 753 includes a first supporting surface 753 a , which is an end surface facing the endless belt 453 , and a second supporting surface 753 b , which is an end surface opposite to the first supporting surface 753 a in the axial direction.
- the first and second supporting surfaces 753 a , 753 b are substantially circular.
- the nonwoven fabric layer 754 rubs the image layer I on the sheet S.
- the nonwoven fabric layer 754 which is made of a nonwoven fabric, is mounted on the entire first supporting surface 753 a and looks circular in a plane. Any of the nonwoven fabrics described in the context of FIG. 4 may be used as the nonwoven fabric.
- the dynamic friction coefficient of the nonwoven fabric is no more than 0.50.
- the backup roller 340 of the belt unit 450 G is arranged such that the surface pressure between the backup roller 340 and a layer surface 754 a of the nonwoven fabric layer 754 becomes, for example, 0.2 g/mm 2 . Therefore, the nonwoven fabric layer 754 keeps in surface contact with the endless belt 453 .
- the layer surface 754 a of the nonwoven fabric layer 754 which contacts the endless belt 453 , forms a rubbing surface.
- the layer thickness of the nonwoven fabric layer 754 is appropriately set such that the nonwoven fabric layer 754 and the image layer I come into smooth contact with each other.
- the nonwoven fabric layer 754 has a rubbing region CR in which the nonwoven fabric layer 754 rubs the image layer I while keeping in surface contact with the image layer I.
- the rubbing region CR is described with reference to FIGS. 53 to 55 .
- FIG. 55 is a plan view of the rubbing member 751 and the endless belt 453 .
- the shaft 755 is fixed to the second supporting surface 753 b of the supporting member 753 at a position where one end of the shaft 755 aligns with the central axis of the supporting member 753 .
- the drive source 752 is, for example, a motor, which is coupled to the other end of the shaft 755 and rotates the shaft 755 in the clockwise direction in FIG. 55 .
- the nonwoven fabric layer 754 has a rotation center O, which conforms with the central axis of the supporting member 753 , and a rotation axis of the shaft 755 (a rotation axis extending in an intersecting direction with the surface of the sheet on which the image layer I is formed).
- the supporting member 753 rotates around the central axis.
- the nonwoven fabric layer 754 mounted on the first supporting surface 753 a of the supporting member 753 also rotates around the rotation center O while keeping in contact with the endless belt 453 .
- the layer surface 754 a of the nonwoven fabric layer 754 is exemplified as the rotation surface.
- the rubbing region CR is a region which is set on the downstream side from the rotation center O of the nonwoven fabric layer 754 when viewed from the conveying direction (the first direction D 1 ) of the sheet S, and looks a substantially semicircular shape in a plane.
- the nonwoven fabric layer 754 contacts the endless belt 453 to form a nip portion N with the endless belt only in the rubbing region CR.
- the entire rubbing region CR of the nonwoven fabric layer 754 comes into surface contact with the sheet S at the nip portion N.
- the position where the backup roller 340 abuts the endless belt 453 and the inclination angle of the shaft 755 with respect to the rubbing member 751 are appropriately adjusted such that the rubbing region CR becomes semicircular.
- FIG. 55 shows a state in which the leading end of the sheet S in the conveying direction (the first direction D 1 ) is in surface contact with the rubbing region CR.
- a linear speed in a tangential direction of the supporting member 753 rotated by the shaft 755 may be greater than the first speed V 1 of conveying the sheet S.
- the diameter of the supporting member 753 (that is the diameter D of the nonwoven fabric layer 754 ) is greater than a sheet width W perpendicular to the conveying direction (the first direction D 1 ) of the sheet S, so that the entire image layer I is rubbed.
- the rubbing region CR of the nonwoven fabric layer 754 which rotates around the rotation center O, keeps in surface contact with the sheet S to rub the image layer I.
- the linear speed LV of the nonwoven fabric layer 754 may be greater than the first speed V 1 of conveying the sheet S.
- the nonwoven fabric layer 754 made of a nonwoven fabric is used as the rubbing surface. Therefore, it becomes easier for the nonwoven fabric layer 754 to bring into surface contact with the sheet S.
- the nonwoven fabric which forms the nonwoven fabric layer 754 , has a dynamic friction coefficient of 0.50 or lower, which is less likely to impinge on the conveyance of the sheet S and to cause a damaged image layer I under the rubbing operation.
- planar nonwoven fabric layer 754 described in the eighteenth embodiment is circular, but the planar nonwoven fabric layer 754 is not particularly limited thereto.
- the planar nonwoven fabric layer 754 may be, for example, a ring shape without a central portion where there is no rubbing region CR of the nonwoven fabric layer 754 .
- the fixing device 750 according to the eighteenth embodiment and the conveyor 400 G which is used for conveying the sheet S to the fixing device 750 are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 56 is a schematic view of a fixing device 750 R and conveyor 400 G according to the nineteenth embodiment.
- the sheet S having the image layer I formed thereon is conveyed to the fixing device 750 R by the conveyor 400 G.
- the configuration of the conveyor 400 G is described with reference to FIG. 53 .
- the fixing device 750 R rubs and fixes the image layer I on the sheet S.
- the fixing device 750 R includes a rubbing member 751 R situated in an opposite side to the backup roller 340 so that the endless belt 453 intervenes between the rubbing member 751 R and the backup roller 340 , and the drive source 752 configured to drive the rubbing member 751 R.
- the rubbing member 751 R includes the supporting member 753 (brush supporting member), a rubbing brush 760 , and the shaft 755 .
- the supporting member 753 is a cylindrical block member.
- the supporting member 753 includes the first supporting surface 753 a which is an end surface facing the endless belt 453 and the second supporting surface 753 b which is an end surface opposite to the first supporting surface 753 a in the axial direction.
- the first and second supporting surfaces 753 a , 753 b are substantially circular.
- the rubbing brush 760 rubs the image layer I on the sheet S.
- the entire first supporting surface 753 a (brush mounting surface) of the supporting member 753 is covered with the rubbing brush 760 .
- the rubbing brush 760 looks circular in a plane.
- the rubbing brush 760 has a brush surface 760 a facing the endless belt 453 , and a number of bristles 761 are implanted in the brush surface 760 a .
- the bristles 761 are implanted in the periphery of the brush surface 760 a .
- a piled woven fabric with electrically-conductive rayon or polyester is exemplified as a material of the bristles 761 . With the electrically-conductive rayon, the pile fineness thereof is 300D/100F. With the polyester, the pile fineness thereof is 75D/12F.
- the tip ends of the bristles 761 of the rubbing brush 760 are pressed against the endless belt 453 to be bent. Therefore, the rubbing brush 760 is in surface contact with the endless belt 453 because of the bent bristles 761 .
- the bent tip ends of the bristles 761 form the rubbing surface.
- the bristles 761 of the rubbing brush 760 are pressed against the endless belt 453 such that the surface pressure applied to the endless belt 453 becomes, for example, 0.2 g/mm 2 . Not only the abovementioned pile fineness but also the density and length of the bristles 761 are appropriately set so as to achieve a given surface pressure.
- the rubbing brush 760 has the rubbing region CR where the rubbing brush 760 rubs the image layer I while keeping in surface contact with the image layer I.
- the rubbing region CR is described with reference to FIGS. 56 to 58 .
- FIG. 58 is a plan view of the rubbing member 751 R and the endless belt 453 .
- the shaft 755 is fixed to the second supporting surface 753 b of the supporting member 753 at a position where the shaft 755 aligns with the central axis of the supporting member 753 .
- the drive source 752 is, for example, a motor which is coupled to the shaft 755 and rotates the shaft 755 in the clockwise direction in FIG. 58 .
- the rubbing brush 760 has a rotation center O which aligns with the central axis of the supporting member 753 and the rotation axis of the shaft 755 .
- the supporting member 753 rotates around the central axis.
- the rubbing brush 760 mounted on the first supporting surface 753 a of the supporting member 753 also rotates around the rotation center O. Meanwhile the bent bristles 761 are kept in contact with the endless belt 453 .
- the rubbing region CR is a region which is set on the downstream side from the rotation center O of the rubbing brush 760 when viewed from the conveying direction (the first direction D 1 ) of the sheet S, and looks a substantially semicircular shape in a plane.
- the bristles 761 of the rubbing brush 760 come into contact with the endless belt 453 to form the nip portion N with the endless belt 453 only in the rubbing region CR.
- the bristles 761 of the rubbing brush 760 in the entire rubbing region CR come into surface contact with the sheet S at the nip portion N.
- FIG. 58 shows a state in which the leading edge of the sheet S in the conveying direction (the first direction D 1 ) enters the rubbing region CR.
- the linear speed in a tangential direction of the supporting member 753 rotated by the shaft 755 may be greater than the first speed V 1 of conveying the sheet S.
- the diameter of the supporting member 753 (that is the diameter D of the rubbing brush 760 ) is greater than the sheet width W perpendicular to the conveying direction (the first direction D 1 ) of the sheet S, so that the entire image layer I is rubbed.
- the contact area of the contact surface between the bristles 761 of the rubbing brush 760 and the image layer I which is the region area of the rubbing region CR where the bristles 761 of the rubbing brush 760 come into surface contact with the image layer I to rub the image layer I, may be switched between a first region area (first contact area) and a second region area (second contact area) larger than the first region area.
- the fixing device 750 R according to the nineteenth embodiment further includes a switching mechanism 780 configured to change the region area of the rubbing region CR, and a controller U configured to control the switching mechanism 780 .
- FIG. 59 shows a state in which the region area of the rubbing region CR is switched to the first region area
- FIG. 60 shows a state in which the region area of the rubbing region CR is switched to the second region area.
- the drive source 752 of the fixing device 750 R is stored in a housing 783 .
- the shaft 755 of the rubbing member 751 R is coupled to the drive source 752 through a hole provided in the housing 783 .
- the housing 783 may be turn in a given range. By turning the housing 783 , the rubbing member 751 R is turned around drive source 752 .
- the switching mechanism 780 includes, for example, a cam 781 and a biasing member 782 .
- the biasing member 782 which is a spring member, for example, applies a basing force in a direction of an arrow B to the housing 783 in order to turn the housing 783 in a given direction (in the counterclockwise direction, in FIG. 56 ).
- the cam 781 abuts and turns the housing 783 in the clockwise direction in FIG. 56 against the biasing force of the biasing member 782 .
- An increase in the intersection angle ⁇ results in greater region area of the rubbing region CR. More specifically, if the intersection angle ⁇ is switched to the first angle, the region area of the rubbing region CR is switched to the first region area. If the intersection angle ⁇ is switched to the second angle, the region area of the rubbing region CR is switched to the second region area.
- the first and second angles are set at 60° and 90°, respectively.
- the controller U controls the switching mechanism 780 to switch the region area of the rubbing region CR between the first and second region areas. Control operations performed by the controller U on the switching mechanism 780 are described hereinafter. If the controller U turns the cam 781 in the first direction to switch the region area of the rubbing region CR from the first region area shown in FIG. 59 to the second region area, the biasing member 782 biases the housing 783 in the direction of the arrow B, and then the housing 783 is turned in the counterclockwise direction in FIG. 56 . By turning the housing 783 in the counterclockwise direction, the rubbing member 751 R also turns around the drive source 752 in the counterclockwise direction. Meanwhile a turning range of the cam 781 and the rubbing member 751 R is set such that the intersection angle ⁇ becomes 90°. As a result, the region area of the rubbing region CR is switched to the second region area greater than the first region area.
- the controller U turns the cam 781 in the second direction opposite to the first direction to switch the region area of the rubbing region CR from the second region area to the first region area as shown in FIG. 60 , the controller U turns the cam 781 in a second direction opposite to the first direction.
- the cam 781 turns against the biasing force of the biasing member 782 , so that the housing 783 is turned in the clockwise direction.
- the rubbing member 751 R also turns around the drive source 752 in the clockwise direction. Meanwhile the turning range of the cam 781 and the rubbing member 751 R is set such that the intersection angle ⁇ becomes 60°. As a result, the region area of the rubbing region CR is switched to the first region area smaller than the second region area.
- the controller U controls the switching mechanism 780 to switch the region area of the rubbing region CR to the first region area (i.e., the intersection angle ⁇ is 60°) for the thin sheet S conveyed to the nip portion N. If the thick sheet S is conveyed to the nip portion P, the controller U controls the switching mechanism 780 to switch the region area of the rubbing region CR to the second region area (i.e., the intersection angle ⁇ is 90°).
- the controller U appropriately changes the rubbing time for rubbing the image layer I with the rubbing brush 760 in response to the thickness of sheets S (the type of the sheet S).
- the controller U and the switching mechanism 780 are exemplified as the adjustment mechanism.
- the rubbing brush 760 rotates around the rotation center O while the bristles 761 in the rubbing region CR are kept in surface contact with the sheet S and rub the image layer I.
- the linear speed LV of the rubbing brush 760 may be greater than the first speed V 1 of conveying the sheet S.
- the components of the liquid developer which forms the image layer I are facilitated to enter into the surface layer of the sheet S, which shortens the time period during which the image layer I is fixed and preferably prevent the image layer I from peeling because of stronger fixation of the image layer I.
- the fixing device 750 R uses the rubbing brush 760 with many bristles 761 to rub the image layer I. Appropriate adjustments of the bristles 761 such as material, pile fineness, density and length cause less impingement on the conveyance of the sheet S and less damage to the image even under the rubbing operation.
- the controller U of the fixing device 750 R appropriately changes the rubbing time period for rubbing the image layer I in response to the thickness of sheets S, by switching the region area of the rubbing region CR between the first and second region areas in response to the thickness of the sheets S. Therefore, even if the sheets S are different in thickness, the components of the liquid developer for forming the image may be facilitated to permeate into the surface layer of the sheets S.
- the rubbing brush 760 with the bristles 761 of the fixing device 750 R is used for rubbing the image layer I. Therefore, the intersection angle ⁇ may be switched between the first and second angles, so that the region area of the rubbing region CR may be easily switched between the first and second region areas.
- the fixing device 750 R according to the nineteenth embodiment and the conveyor 400 G, which is used for conveying the sheet S to the fixing device 750 R, are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 61 is a plan view of the rubbing member 751 R and the endless belt 453 .
- two rubbing members a first rubbing member 1751 and second rubbing member 2751 , are used.
- the first and second rubbing members 1751 , 2751 are situated side by side in a direction perpendicular to the conveying direction (the first direction D 1 ) of the sheet S.
- a first rubbing surface (tip ends of first bristles 1761 ) formed by a first rubbing brush 1760 of the first rubbing member 1751 and a second rubbing surface (tip ends of second bristles 2761 ) formed by a second rubbing brush 2760 of the second rubbing member 2751 are situated side by side in the direction (a width direction W of the sheet S (a transverse direction T)) perpendicular to the conveying direction (the first direction D 1 ) of the sheet S. Therefore, even if a color image layer I with an increased carrier liquid amount is fixed to the sheet S, the carrier liquid may be facilitated to enter the surface layer of the sheet S.
- the first rubbing brush 1760 is exemplified as the first brush.
- the second rubbing brush 2760 is exemplified as the second brush.
- a first shaft 1755 of the first rubbing member 1751 is rotated by the drive source 752 in a first rotation direction R 1 (the clockwise direction in FIG. 61 ), and a second shaft 2755 of the second rubbing member 2751 is rotated by the drive source 752 in a second rotation direction R 2 (the counterclockwise direction in FIG. 61 ) opposite to the first rotation direction R 1 . Therefore, the first rubbing brush 1760 rubs the image layer I while rotating in the first rotation direction R 1 , and the second rubbing brush 2760 rubs the image layer I while rotating in the second rotation direction R 2 .
- the sheet S is consequently rubbed while being stretched to prevent wrinkles on the sheet S.
- the rubbing surface formed by the first rubbing brush 1760 is exemplified as the first rotation surface.
- the rubbing surface formed by the second rubbing brush 2760 is exemplified as the second rotation surface.
- the first and second rubbing members 1751 , 2751 are situated such that the first bristles 1761 of the first rubbing brush 1760 and the second bristles 2761 of the second rubbing brush 2760 come into contact with each other in the perpendicular direction to the conveying direction (the first direction D 1 ) of the sheet S.
- a contact area OA where the first and second bristles 1761 , 2761 come into contact with each other is formed between the first and second rubbing members 1751 , 2751 . Therefore it is less likely that there are non-rubbing regions where the image layer I is not rubbed.
- FIG. 61 shows the configuration which uses two brushes, the first and second rubbing brushes 1760 , 2760 .
- two nonwoven fabric layers such as first and second nonwoven fabric layers may be situated side by side in the perpendicular direction to the conveying direction (the first direction D 1 ) of the sheet S.
- FIG. 62 Modifications from the eighteenth embodiment are described with reference to FIG. 62 hereinafter.
- the configuration according to the eighteenth embodiment described with reference to FIGS. 53 to 55 has the nonwoven fabric layer 754 , which is partially brought into surface contact with the endless belt 453 .
- methodologies of the present invention is not limited to such a configuration, so that the entire nonwoven fabric layer 754 may be brought into contact with the endless belt 453 to rub the image layer I, as shown in FIG. 62 .
- a support plate 785 configured to support the entire surface of the nonwoven fabric layer 754 is disposed on the opposite side of the nonwoven fabric layer 754 so that the endless belt 453 intervenes between the nonwoven fabric layer 754 and the support plate 785 .
- the surface pressure applied to the endless belt 453 by the nonwoven fabric layer 754 is appropriately adjusted in order to prevent the image layer I from being excessively rubbed by the nonwoven fabric layer 754 .
- the rubbing brush. 760 may be used in place of the nonwoven fabric layer 754 . In this case, the entire rubbing brush 760 is brought into contact with the endless belt 453 .
- FIG. 63 is a schematic view of a fixing device 1050 and the conveyor 400 G according to the twentieth embodiment.
- FIG. 64 is a perspective view of the fixing device 1050 and the conveyor 400 G.
- the same reference numerals are used for describing the same elements as those of the aforementioned embodiments. The descriptions associated with the aforementioned embodiments are preferably incorporated into the elements which are not described hereinafter.
- the sheet S having the image layer I formed thereon is conveyed to the fixing device 1050 by the conveyor 400 G.
- the conveyor 400 G comprises the belt unit 450 G, the upstream guider 460 situated before the belt unit 450 G, and the downstream guider 469 situated after the belt unit 450 G.
- the sheet S is guided by the upstream guider 460 and sent to the belt unit 450 G. Thereafter, the sheet S is sent to the downstream guide 469 by the belt unit 450 G.
- the belt unit 450 G comprises the drive roller 451 , the idler 452 , the endless belt 453 (conveying belt) extending between the drive roller 451 and the idler 452 , and the tension roller 454 applying tension to the endless belt 453 .
- Rotation of the drive roller 451 causes the endless belt 453 to revolve around the drive roller 451 , the idler 452 and the tension roller 454 .
- the idler 452 and the tension roller 454 rotate in response to the revolution of the endless belt 453 .
- the sheet S which is sent from the upstream guider 460 to the endless belt 453 , moves toward the downstream guider 469 in response to the revolution of the endless belt 453 .
- Reference numeral D 1 represents a direction in which the sheet S is moved from the upstream guider 460 toward the downstream guider 469 by the belt unit 450 G.
- the belt unit 450 G is exemplified as the conveying element.
- the belt unit 450 G further comprises the backup roller 340 disposed inside the endless belt 453 .
- the backup roller 340 abuts the inner surface of the endless belt 453 to support the endless belt 453 between the drive roller 451 and the idler 452 , which is situated on the opposite side to the tension roller 454 .
- the fixing device 1050 fixes the image layer I on the sheet S.
- the fixing device 1050 includes a rubbing member 1051 , a drive source 1054 , and a biasing member 1055 .
- the rubbing member 1051 includes a supporting member 1052 and a nonwoven fabric layer 1053 .
- the supporting member 1052 is an elongated box, which is situated on the opposite side to the backup roller 340 , so that the endless belt 453 intervenes between the supporting member 1052 and the backup roller 340 .
- the supporting member 1052 extends in a width direction of the endless belt 453 and an axial direction of the backup roller 340 .
- the supporting member 1052 has a first supporting surface 1052 a facing the endless belt 453 and a second supporting surface 1052 b opposite to the first supporting surface 1052 a .
- the first supporting surface 1052 a is curved along the conveying direction of the sheet S.
- the second supporting surface 1052 b is substantially flat.
- the nonwoven fabric layer 1053 rubs the image layer I on the sheet S.
- the nonwoven fabric layer 1053 is formed from a nonwoven fabric and entirely attached on the first supporting surface 1052 a . Therefore, the nonwoven fabric layer 1053 extends in the form of an arc along the conveying direction (the first direction D 1 ) of the sheet S. Any of the nonwoven fabrics described in the context of FIG. 4 is used as the nonwoven fabric.
- the dynamic friction coefficient of the nonwoven fabric is 0.50 or lower.
- the surface of the nonwoven fabric layer 1053 rubbing the image layer I on the sheet S is exemplified as the contact surface.
- the biasing member 1055 is, for example, a spring member mounted on the second supporting surface 1052 b of the supporting member 1052 .
- the biasing member 1055 is mounted in each longitudinal end of the supporting member 1052 .
- the biasing member 1055 applies a biasing force F to the supporting member 1052 to allow the nonwoven fabric layer 1053 to keep in contact with the endless belt 453 .
- a nip portion N is formed between a layer surface 1053 a of the nonwoven fabric layer 1053 , which contacts the endless belt 453 , and the endless belt 453 . Therefore, the layer surface 1053 a of the nonwoven fabric layer 1053 forms a rubbing surface.
- the biasing member 1055 is set such that the nonwoven fabric layer 1053 is pressed against the endless belt 453 at a surface pressure of, for example, 0.2 g/mm 2 .
- the layer thickness of the nonwoven fabric layer 1053 is appropriately set such that the nonwoven fabric layer 1053 and the image layer I come into smooth contact with each other.
- the drive source 1054 is held in an appropriate section (for example, a substantially intermediate portion of the supporting member 1052 in a longitudinal direction) inside the supporting member 1052 .
- the drive source 1054 stored in the supporting member 1052 vibrates the supporting member 1052 .
- a vibration motor is exemplified as the drive source 1054 .
- FIG. 65 is a perspective view showing a schematic configuration of the vibration motor.
- the vibration motor 1054 with an inner rotor structure comprises a main body 1056 , an output shaft 1057 , and an eccentric piece 1058 .
- the eccentric piece 1058 is, for example, a weight which is externally fitted to the outer shaft 1057 in order to disrupt a dynamic balance of the main body 1056 . Rotation of the main body 1056 causes vibration because the gravity center of the eccentric piece 1058 is not centered.
- the vibration caused by the vibration motor 1054 vibrates the supporting member 1052 storing the vibration motor 1054 and the nonwoven fabric layer 1053 mounted on the first supporting surface 1052 a of the supporting member 1052 .
- the nonwoven fabric layer 1053 keeps the state where the nonwoven fabric layer 1053 is pressed against the endless belt 453 by the biasing member 1055 as described above. Therefore, when the sheet S is conveyed to the nip portion N, the nonwoven fabric layer 1053 utilizes the vibration to slide on the image layer I in multiple directions to rub the image layer I while keeping in contact with the image layer I without separating therefrom.
- FIG. 66 is a plan view of the endless belt 453 , on which the sheet S is placed, schematically showing the rubbing operation performed on the image layer I by the nonwoven fabric layer 1053 . It should be noted that FIG. 66 does not show the fixing device 1050 for clarification.
- the nonwoven fabric layer 1053 in the rubbing region CR shown by the dashed line in FIG. 66 contacts the endless belt 453 , the sheet S and the image layer I.
- the rubbing region CR is situated on a line connecting a curvature center of the first supporting surface 1052 of the supporting member 1052 with the rotation center of the backup roller 340 , and extends in the sheet width direction W (a transverse direction T) perpendicular to the conveying direction (the first direction D 1 ) of the sheet S.
- the rubbing region CR extends somewhat beyond the width of the sheet S.
- the nonwoven fabric layer 1053 rubs the image layer I while sliding on the image layer I in the rubbing region CR in multiple directions.
- the vibration of the nonwoven fabric layer 1053 reciprocates the rubbing section VP with a small amplitude in conveying direction (the first direction D 1 ) of the sheet S, in the traverse direction T perpendicular to the conveying direction (the first direction D 1 ) of the sheet S, or in an oblique direction K, which is oblique to the conveying direction (the first direction D 1 ) or the traverse direction T.
- the rubbing section VP slides irregularly on the image layer I in multiple directions including these directions D 1 , T, K with small amplitudes to rub the image layer I.
- the section of the image layer I into contact with the rubbing section VP is rubbed a number of times. It should be noted that the rubbing section VP does not necessarily reciprocate in these directions D 1 , T, K.
- the nonwoven fabric layer 1053 is vibrated by the vibration motor 1054 to rub the image layer I in multiple directions while keeping in contact with the image layer I. Therefore, the image layer I on the sheet S is rubbed a number of times by the nonwoven fabric layer 1053 .
- the components of the liquid developer forming the image layer I may be facilitated to enter the surface layer of the sheet S, which may reduce the time period during which the image layer I is fixed and preferably prevent the image layer I from peeling because of stronger fixation of the image layer I.
- the vibration motor is used as the drive source 1054 . Therefore, the nonwoven fabric layer 1053 may vibrate with respect to the image layer I in multiple directions.
- the nonwoven fabric layer 1053 is allowed to keep in contact with the image layer I by the biasing member 1055 . Accordingly, the vibration of the nonwoven fabric layer 1053 is easily transmitted the image layer I.
- the backup roller 340 is disposed on the opposite side to the nonwoven fabric layer 1053 so that the endless belt 453 intervenes between the backup roller 340 and the nonwoven fabric layer 1053 . Therefore, the vibration of the nonwoven fabric layer 1053 is easily transmitted to the image.
- the nonwoven fabric layer 1053 made of a nonwoven fabric is used as a rubbing member for the image layer I.
- the dynamic friction coefficient of the nonwoven fabric is 0.50 or lower, which result in less impingement on the conveyance of the sheet S as well as less damage to the image layer I under the rubbing operation.
- the fixing device 1050 according to the twentieth embodiment and the conveyor 400 G, which is used for conveying the sheet S to the fixing device 1050 , are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 67 is a schematic view of the fixing device 3500 and the conveyor 400 G according to the twenty-first embodiment.
- the sheet S having the image layer I formed thereon is conveyed to the fixing device 3500 by the conveyor 400 G.
- the configuration of the conveyor 400 G is described with reference to FIG. 63 .
- the fixing device 3500 rubs and fixes the image layer I onto the sheet S.
- the fixing device 3500 includes a rubbing member 3510 , the drive source 1054 , and the biasing member 1055 .
- the rubbing member 3510 has a supporting member 3520 and a nonwoven fabric layer 3530 .
- the supporting member 3520 is an elongated box which is situated on the opposite side to the backup roller 340 , so that the endless belt 453 intervenes between the supporting member 3520 and backup roller 340 .
- the supporting member 3520 extends in the width direction of the endless belt 453 and the axial direction of the backup roller 340 .
- the supporting member 3520 has a first supporting surface 3520 a facing the endless belt 453 and a second supporting surface 3520 b opposite to the first supporting surface 3520 a .
- the first supporting surface 3520 a has a curved surface portion 3520 aa .
- the curved surface portion 3520 aa is curved along the outer circumferential surface of the backup roller 340 .
- the second supporting surface 3520 b is substantially flat.
- the nonwoven fabric layer 3530 rubs the image layer I on the sheet S.
- the nonwoven fabric layer 3530 is formed from a nonwoven fabric and entirely mounted on the first supporting surface 3520 a . Therefore, the nonwoven fabric layer 3530 has an arc section 3530 a corresponding to the curved surface portion 3520 aa of the first supporting surface 3520 a . Any of the nonwoven fabrics'described in the context of FIG. 4 is used as the nonwoven fabric.
- the dynamic friction coefficient of the nonwoven fabric is 0.50 or lower.
- the biasing member 1055 is, for example, a spring member mounted on the second supporting surface 3520 b of the supporting member 3520 . In the twenty-first embodiment as well, although not shown, the biasing member 1055 is mounted in each longitudinal end of the supporting member 3520 .
- the biasing member 1055 applies a biasing force F to the supporting member 3520 to press the nonwoven fabric layer 3530 against the endless belt 453 to keep the surface contact between the entire arc section 3530 a of the nonwoven fabric layer 3530 and the endless belt 453 .
- a nip portion N is formed between the arc section 3530 a of the nonwoven fabric layer 3530 and the endless belt 453 .
- the layer surface of the arc section 3530 a of the nonwoven fabric layer 3530 forms a rubbing surface.
- the biasing member 1055 is set such that the arc section 3530 a of the nonwoven fabric layer 3530 is pressed against the endless belt 453 at a surface pressure of, for example, 0.2 g/mm 2 .
- the layer thickness of the nonwoven fabric layer 3530 is appropriately set such that the nonwoven fabric layer 3530 and the image layer I come into smooth contact with each other.
- the drive source 1054 is stored in the supporting member 3520 , and the same vibration motor as that of the twentieth embodiment is used.
- the vibration generated by the vibration motor 1054 vibrates the supporting member 3520 storing the vibration motor 1054 and the nonwoven fabric layer 3530 mounted on the first supporting surface 3520 a of the supporting member 3520 .
- the arc section 3530 a of the nonwoven fabric layer 3530 keeps its state where the arc section 3530 a is brought into surface contact with the endless belt 453 by the biasing member 1055 as described above.
- the arc section 3530 a of the nonwoven fabric layer 3530 utilizes the vibration to slide on the image layer I in multiple directions to rub the image layer I while keeping in surface contact with the image layer I without separating therefrom.
- the arc section 3530 a of the nonwoven fabric layer 3530 rubs the image layer I while keeping in surface contact with the image layer I. Therefore, the vibration of the arc section 3530 a is widely transmitted to the image layer I.
- a wide range of the image layer I on the sheet S is rubbed a number of times by the nonwoven fabric layer 3530 . Accordingly, the components of the liquid developer forming the image layer I may be facilitated to enter the surface layer of the sheet S, which may shorten the time period during which the image layer I is fixed and preferably prevent the image layer I from peeling because of stronger fixation of the image layer I.
- the nonwoven fabric layer 3530 made of a nonwoven fabric is used as the rubbing surface.
- the nonwoven fabric layer 3530 may easily be brought into surface contact with the image layer I.
- the use of the nonwoven fabric with a low dynamic friction coefficient (0.5 or lower) is less likely to impinge on the conveyance of the sheet S and to damage the image layer I under the rubbing operation of the nonwoven fabric layer 3530 .
- the fixing device 3500 according to the twenty-first embodiment and the conveyor 400 G, which is used for conveying the sheet S to the fixing device 3500 , are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor which are described in the context of the first embodiment.
- FIG. 68 is a schematic view of the fixing device 3600 and the conveyor 400 G according to the twenty-second embodiment.
- the nonwoven fabric layers 1053 and 3530 are used for rubbing the image layer I, but a rubbing brush 1062 may be used for rubbing the image layer I in the twenty-second embodiment as shown in FIG. 68 .
- the fixing device 3600 shown in FIG. 68 includes a rubbing member 1060 , the drive source 1054 , and the biasing member 1055 .
- the rubbing member 1060 includes a supporting member 1061 and the rubbing brush 1062 .
- the supporting member 1061 is an elongated box which is situated on the opposite side to the backup roller 340 , so that the endless belt 453 intervenes between the supporting member 1061 and the backup roller 340 .
- the supporting member 1061 extends in the width direction of the endless belt 453 and the axial direction of the backup roller 340 .
- the supporting member 1061 includes a first supporting surface 1061 a facing the endless belt 453 and a second supporting surface 1061 b opposite to the first supporting surface 1061 a .
- the first and second supporting surface 1061 a , 1061 b are substantially flat.
- the rubbing brush 1062 is mounted on the first supporting surface 1061 a of the supporting member 1061 .
- the rubbing brush 1062 includes a brush surface 1062 a facing the endless belt 453 .
- a number of bristles 1063 are implanted in the brush surface 1062 a .
- a range in which the bristles 1063 are implanted is appropriately set.
- the bristles 1063 are implanted only in a position on the brush surface 1062 a which contacts the endless belt 453 .
- a piled woven fabric formed from electrically-conductive rayon or polyester is exemplified as a material of the bristles 1063 . With the electrically-conductive rayon, the pile fineness thereof is 300D/100F. With the polyester, the pile fineness thereof is 75D/12F.
- the biasing member 1055 is mounted on the second supporting surface 1061 b of the supporting member 1061 .
- the biasing member 1055 applies a biasing force F to the supporting member 1061 and then to the rubbing brush 1062 , in order to press the bristles 1063 of the rubbing brush 1062 against the endless belt 453 . Accordingly, the tip ends of the bristles 1063 of the rubbing brush 1062 are pressed against the endless belt 453 to be bent. Therefore, the rubbing brush 1062 with the bent bristles 1063 is in surface contact with the endless belt 453 . The bent tip ends of the bristles 1063 form the rubbing surface.
- the bristles 1063 of the rubbing brush 1062 are pressed against the endless belt 453 such that the surface pressure applied to the endless belt 453 becomes, for example, 0.2 g/mm 2 . Not only the abovementioned pile fineness but also the density and length of the bristles 1063 are appropriately set so as to obtain a given surface pressure.
- the drive source 1054 is stored in the supporting member 1061 , and the same vibration motor 1054 as those of the twentieth and twenty-first embodiments is used.
- the vibration generated by the vibration motor 1054 vibrates the supporting member 1061 storing the vibration motor 1054 and the rubbing brush 1062 mounted on the first supporting surface 1061 a of the supporting member 1061 .
- the tip ends of the bristles 1063 of the rubbing brush 1062 keep the state where the tip ends of the bristles 1063 are brought into surface contact with the endless belt 453 by the biasing member 1055 as described above.
- the bristles 1063 of the rubbing brush 1062 utilize the vibration to slide on the image layer I in multiple directions to rub the image layer I while keeping in surface contact with the image layer I without separating therefrom.
- the bristles 1063 of the rubbing brush 1062 slides on the image layer I while keeping surface contact therewith to rub the image layer I. Consequently, the image layer I on the sheet S is rubbed a number of times by the bristles 1063 of the rubbing brush 1062 . Therefore, the components of the liquid developer forming the image layer I may be facilitated to enter the surface layer of the sheet S, which may shorten the time period during which the image layer I is fixed and preferably prevent the image layer I from peeling because of stronger fixation of the image layer I.
- the fixing device 3600 according to the twenty-second embodiment and the conveyor 400 G which is used for conveying the sheet S to the fixing device 3600 are preferably incorporated in the color printer 1 described in the context of FIGS. 8 to 10 , in place of the fixing device 300 and the conveyor described in the context of the first embodiment.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fixing For Electrophotography (AREA)
- Wet Developing In Electrophotography (AREA)
- Color Electrophotography (AREA)
Abstract
Description
FR(%)=D 1 /D 0×100 [Formula 1]
(d) Tricyclo [4.3.0.12,5]deca-3,7-diene (dicyclopentadiene), tricyclo [4.3.0.12,5]deca-3-ene;
(e) Tricyclo [4.4.0.12,5]undeca-3,7-diene or tricyclo [4.4.0.12,5]undeca-3,8-diene or tricyclo [4.4.0.12,5]undeca-3-ene that is a partially hydrogenated product (or an adduct of cyclopentadiene and cyclohexane) thereof;
(f) 5-cyclopentyl bicyclo [2.2.1]hept-2-ene, 5-cyclohexyl-bicyclo [2.2.1]hept-2-ene, 5-cyclohexenyl bicyclo [2.2.1]hept-2-ene, 5-phenyl-bicyclo [2.2.1]hept-2-ene, and other three-ring cyclic olefins;
(g) Tetracyclo [4.4.0.12, 5.17,10]dodeca-3-ene (tetracyclododecene), 8-methyltetracyclo [4.4.0.12, 5.17,10]dodeca-3-ene, 8-ethyltetracyclo [4.4.0.12, 5.17,10]dedeca-3-ene, 8-methylidenetetracyclo [4.4.0.12, 5.17,10]dodeca-3-ene, 8-ethylidenetetracyclo [4.4.0.12, 5.17,10]dodeca-3-ene, 8-vinyltetracyclo [4.4.0.12, 5.17,10]dodeca-3-ene, 8-propenyl-tetracyclo [4.4.0.12, 5.17,10]dodeca-3-ene, and other four-ring cyclic olefins;
(h) 8-cyclopentyl-tetracyclo [4.4.0.12, 5.17,10]dodeca-3-ene, 8-cyclohexyl-tetracyclo [4.4.0.12, 5.17,10]dodeca-3-ene, 8-cyclohexenyl-tetracyclo [4.4.0.12, 5.17,10]dodeca-3-ene, and 8-phenyl-cyclopentyl-tetracyclo [4.4.0.12, 5.17,10]dodeca-3-ene;
(i) Tetracyclo [7.4.13, 6.01,9.02,7]tetradeca-4,9,11,13-tetraene (1,4-methano-1,4,4a,9a-tetrahydrofluorene), tetracyclo [8.4.14, 7.01,10.03,8]pentadeca-5,10,12,14-tetraene (1,4-methano-1,4,4a,5,10,10a-hexahydroanthracene);
(j) Pentacyclo [6.6.1.13, 6.02,7.09,14]-4-hexadecene, pentacyclo [6.5.1.13, 6.02,7.09,13]-4-pentadecene, pentacyclo [7.4.0.02, 7.13,6.110,13]-4-pentadecene, heptacyclo [8.7.0.12, 9.14,7.111, 17.03,8.012,16]-5-eicosene, heptacyclo [8.7.0.12, 9.03,8.14, 7.012,17.113,16]-14-eicosene; and
(k) Polycyclic olefins such as tetramers of cyclopentadiene. These cyclic olefins may be used alone or in combinations of two or more thereof.
[A-B]x-A (Chemical Formula 1)
-
- (Where x represents an integer chosen such that the number molecular average weight ranges from 1,000 to 100,000.)
(where R1, R2, R4, R5 and R6 each represent a hydrogen atom or methyl group; R3 represents a hydrogen atom, a halogen atom, a phenyl group or a saturated alkyl group, a methoxy group or ethoxy group having 1 to 20 carbon atoms; and m, n each represent an integer chosen such that the content of the polymer block A ranges from 5 to 75 mass %.)
Claims (20)
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JP2010-177638 | 2010-08-06 | ||
JP2010177638 | 2010-08-06 | ||
JP2010-237189 | 2010-10-22 | ||
JP2010237189A JP5622522B2 (en) | 2010-08-06 | 2010-10-22 | Image forming apparatus |
JP2010237192A JP5677803B2 (en) | 2010-08-06 | 2010-10-22 | Image forming apparatus |
JP2010-237187 | 2010-10-22 | ||
JP2010-237191 | 2010-10-22 | ||
JP2010237187A JP5637811B2 (en) | 2010-08-06 | 2010-10-22 | Image forming apparatus |
JP2010237190A JP5677801B2 (en) | 2010-08-06 | 2010-10-22 | Image forming apparatus |
JP2010-237186 | 2010-10-22 | ||
JP2010-237192 | 2010-10-22 | ||
JP2010237188A JP5553725B2 (en) | 2010-08-06 | 2010-10-22 | Image forming apparatus and fixing device |
JP2010-237188 | 2010-10-22 | ||
JP2010237191A JP5677802B2 (en) | 2010-08-06 | 2010-10-22 | Image forming apparatus and fixing device |
JP2010237186A JP5637810B2 (en) | 2010-08-06 | 2010-10-22 | Image forming apparatus |
JP2010-237190 | 2010-10-22 |
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Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5323129B2 (en) * | 2011-05-24 | 2013-10-23 | 京セラドキュメントソリューションズ株式会社 | Image forming apparatus |
JP5409821B2 (en) * | 2012-01-23 | 2014-02-05 | 京セラドキュメントソリューションズ株式会社 | Image forming apparatus |
JP6369647B2 (en) * | 2016-02-18 | 2018-08-08 | 京セラドキュメントソリューションズ株式会社 | Toner for electrostatic latent image development |
JP6451665B2 (en) * | 2016-03-01 | 2019-01-16 | 京セラドキュメントソリューションズ株式会社 | Glossiness imparting device and image forming apparatus having the same |
PL3222795T3 (en) | 2016-03-23 | 2023-01-02 | Li & Co AG | Wall or floor covering element |
US10114322B2 (en) * | 2016-08-26 | 2018-10-30 | Ricoh Company, Ltd. | Fixing device and image forming apparatus |
Citations (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0784457A (en) | 1993-09-16 | 1995-03-31 | Nippon Telegr & Teleph Corp <Ntt> | Electrostatic recorder |
JPH08115004A (en) | 1994-10-13 | 1996-05-07 | Ricoh Co Ltd | Fixing device |
JP2001290382A (en) | 2000-04-10 | 2001-10-19 | Ricoh Co Ltd | Image glossiness adjusting device and image forming device |
JP2001290383A (en) | 2000-04-05 | 2001-10-19 | Canon Inc | Image forming device |
JP2002268428A (en) | 2001-03-09 | 2002-09-18 | Ricoh Co Ltd | Fixing device and fixing roller in image forming device and method of working surface material of pressure roller or belt |
US6459878B1 (en) * | 1999-09-30 | 2002-10-01 | Canon Kabushiki Kaisha | Heating assembly, image-forming apparatus, and process for producing silicone rubber sponge and roller |
JP2004240172A (en) | 2003-02-06 | 2004-08-26 | Ricoh Co Ltd | Fixing device |
JP2005049462A (en) | 2003-07-30 | 2005-02-24 | Ricoh Co Ltd | Fixing device and image forming apparatus |
JP2006106151A (en) | 2004-10-01 | 2006-04-20 | Konica Minolta Business Technologies Inc | Fixing device and image forming apparatus |
US20060127142A1 (en) | 2004-12-13 | 2006-06-15 | Canon Kabushiki Kaisha | Image heating device |
JP2007025500A (en) | 2005-07-20 | 2007-02-01 | Sharp Corp | Fixing device and image forming apparatus |
JP2008090116A (en) | 2006-10-04 | 2008-04-17 | Seiko Epson Corp | Image forming apparatus and image forming method |
US20080118856A1 (en) | 2004-12-20 | 2008-05-22 | Olga Ivanova | Marking Liquid |
US7437111B2 (en) * | 2004-02-16 | 2008-10-14 | Ricoh Company Limited | Fixing device, and image forming apparatus using the fixing device |
JP2009075180A (en) | 2007-09-19 | 2009-04-09 | Ricoh Co Ltd | Fixing method, fixing device, image forming method, and image forming device |
JP2009098474A (en) | 2007-10-18 | 2009-05-07 | Seiko Epson Corp | Image forming apparatus and image forming method |
US20090123203A1 (en) | 2007-11-09 | 2009-05-14 | Canon Kabushiki Kaisha | Image heating apparatus and image heating rotational body to be mounted on the image heating apparatus |
JP2009116262A (en) | 2007-11-09 | 2009-05-28 | Canon Inc | Image heating apparatus |
US20090208264A1 (en) | 2007-02-19 | 2009-08-20 | Ricoh Company, Ltd. | Fixing device and image forming apparatus including same |
JP2009222818A (en) | 2008-03-14 | 2009-10-01 | Ricoh Co Ltd | Fixing device and printer having the same |
JP2010139984A (en) | 2008-12-15 | 2010-06-24 | Konica Minolta Business Technologies Inc | Fixing device and image forming apparatus with the same |
Family Cites Families (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1468598A (en) * | 1974-05-01 | 1977-03-30 | Australia Res Lab | Method of and means for image development in electrostatic printing |
US4419003A (en) * | 1980-08-27 | 1983-12-06 | Hitachi, Ltd. | Recording sheet conveying system of pressure fixing type electrostatic printing apparatus |
NL8103867A (en) * | 1981-08-19 | 1983-03-16 | Oce Nederland Bv | METHOD AND APPARATUS FOR TRANSFERRING AND FIXING POWDER IMAGES. |
JPS61121076A (en) * | 1984-11-16 | 1986-06-09 | Canon Inc | Cleaning device |
JPS6259985A (en) * | 1985-09-11 | 1987-03-16 | Toshiba Corp | Pressure fixing method |
JPS635351A (en) * | 1986-06-26 | 1988-01-11 | Ricoh Co Ltd | Liquid developing agent for electrostatic photography |
JPS63116181A (en) * | 1986-11-04 | 1988-05-20 | Matsushita Graphic Commun Syst Inc | Pressure fixing device |
JPH01316780A (en) * | 1988-06-16 | 1989-12-21 | Nec Corp | Fixing device for electrophotographic printer |
JPH0279054A (en) * | 1988-09-16 | 1990-03-19 | Ricoh Co Ltd | Image forming method using liquid developer |
JPH03132687A (en) * | 1989-10-18 | 1991-06-06 | Brother Ind Ltd | Clear coating device |
JPH08190289A (en) * | 1995-01-10 | 1996-07-23 | Canon Inc | Image forming device |
JP2008020726A (en) * | 2006-07-13 | 2008-01-31 | Konica Minolta Business Technologies Inc | Heat fixing device |
JP5300202B2 (en) * | 2007-02-20 | 2013-09-25 | キヤノン株式会社 | Image heating device |
JP2009251087A (en) * | 2008-04-02 | 2009-10-29 | Konica Minolta Business Technologies Inc | Wet developer |
JP2010177638A (en) | 2009-02-02 | 2010-08-12 | Mitsui Chemicals Inc | Organic transistor |
JP5349227B2 (en) | 2009-03-10 | 2013-11-20 | 株式会社東芝 | Car navigation system and individual function device for image signal output |
JP2010237187A (en) | 2009-03-10 | 2010-10-21 | Fuji Xerox Co Ltd | Abnormality detector and program |
JP5233835B2 (en) | 2009-03-11 | 2013-07-10 | 住友化学株式会社 | Eddy current flaw detection probe |
JP5342421B2 (en) | 2009-03-11 | 2013-11-13 | 信越化学工業株式会社 | Method for producing molecular immobilization substrate |
JP2010237189A (en) | 2009-03-11 | 2010-10-21 | Fujifilm Corp | Three-dimensional shape measuring method and device |
JP4748264B2 (en) | 2009-03-12 | 2011-08-17 | 株式会社デンソー | Navigation device |
JP4543186B1 (en) | 2009-03-13 | 2010-09-15 | 国立大学法人茨城大学 | Nitrogen dioxide photolysis converter and nitrogen oxide concentration measuring apparatus equipped with nitrogen dioxide photolysis converter |
-
2011
- 2011-08-03 CN CN201110221460.3A patent/CN102375358B/en not_active Expired - Fee Related
- 2011-08-03 US US13/197,360 patent/US8693931B2/en not_active Expired - Fee Related
- 2011-08-04 EP EP11006438.3A patent/EP2416224B1/en not_active Not-in-force
Patent Citations (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0784457A (en) | 1993-09-16 | 1995-03-31 | Nippon Telegr & Teleph Corp <Ntt> | Electrostatic recorder |
JPH08115004A (en) | 1994-10-13 | 1996-05-07 | Ricoh Co Ltd | Fixing device |
US6459878B1 (en) * | 1999-09-30 | 2002-10-01 | Canon Kabushiki Kaisha | Heating assembly, image-forming apparatus, and process for producing silicone rubber sponge and roller |
JP2001290383A (en) | 2000-04-05 | 2001-10-19 | Canon Inc | Image forming device |
JP2001290382A (en) | 2000-04-10 | 2001-10-19 | Ricoh Co Ltd | Image glossiness adjusting device and image forming device |
JP2002268428A (en) | 2001-03-09 | 2002-09-18 | Ricoh Co Ltd | Fixing device and fixing roller in image forming device and method of working surface material of pressure roller or belt |
JP2004240172A (en) | 2003-02-06 | 2004-08-26 | Ricoh Co Ltd | Fixing device |
JP2005049462A (en) | 2003-07-30 | 2005-02-24 | Ricoh Co Ltd | Fixing device and image forming apparatus |
US7437111B2 (en) * | 2004-02-16 | 2008-10-14 | Ricoh Company Limited | Fixing device, and image forming apparatus using the fixing device |
JP2006106151A (en) | 2004-10-01 | 2006-04-20 | Konica Minolta Business Technologies Inc | Fixing device and image forming apparatus |
US20060127142A1 (en) | 2004-12-13 | 2006-06-15 | Canon Kabushiki Kaisha | Image heating device |
US20090208265A1 (en) | 2004-12-13 | 2009-08-20 | Canon Kabushiki Kaisha | Image heating device |
US20080213013A1 (en) | 2004-12-13 | 2008-09-04 | Canon Kabushiki Kaisha | Image heating device |
US20080118856A1 (en) | 2004-12-20 | 2008-05-22 | Olga Ivanova | Marking Liquid |
JP2007025500A (en) | 2005-07-20 | 2007-02-01 | Sharp Corp | Fixing device and image forming apparatus |
JP2008090116A (en) | 2006-10-04 | 2008-04-17 | Seiko Epson Corp | Image forming apparatus and image forming method |
US20090208264A1 (en) | 2007-02-19 | 2009-08-20 | Ricoh Company, Ltd. | Fixing device and image forming apparatus including same |
JP2009075180A (en) | 2007-09-19 | 2009-04-09 | Ricoh Co Ltd | Fixing method, fixing device, image forming method, and image forming device |
JP2009098474A (en) | 2007-10-18 | 2009-05-07 | Seiko Epson Corp | Image forming apparatus and image forming method |
US20090123203A1 (en) | 2007-11-09 | 2009-05-14 | Canon Kabushiki Kaisha | Image heating apparatus and image heating rotational body to be mounted on the image heating apparatus |
JP2009116262A (en) | 2007-11-09 | 2009-05-28 | Canon Inc | Image heating apparatus |
US20130251429A1 (en) | 2007-11-09 | 2013-09-26 | Canon Kabushiki Kaisha | Image heating apparatus and image heating rotational body to be mounted on the image heating apparatus |
JP2009222818A (en) | 2008-03-14 | 2009-10-01 | Ricoh Co Ltd | Fixing device and printer having the same |
JP2010139984A (en) | 2008-12-15 | 2010-06-24 | Konica Minolta Business Technologies Inc | Fixing device and image forming apparatus with the same |
Also Published As
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EP2416224A3 (en) | 2014-07-30 |
EP2416224B1 (en) | 2016-05-11 |
EP2416224A2 (en) | 2012-02-08 |
US20120034003A1 (en) | 2012-02-09 |
CN102375358A (en) | 2012-03-14 |
CN102375358B (en) | 2015-04-22 |
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